diff --git a/fastNLP/core/dataset.py b/fastNLP/core/dataset.py
index 3b5ebbbe..bc4dcf57 100644
--- a/fastNLP/core/dataset.py
+++ b/fastNLP/core/dataset.py
@@ -1,7 +1,9 @@
+import _pickle as pickle
 import numpy as np
 
 from fastNLP.core.fieldarray import FieldArray
 from fastNLP.core.instance import Instance
+from fastNLP.core.utils import get_func_signature
 
 _READERS = {}
 
@@ -26,24 +28,6 @@ class DataSet(object):
     However, it stores data in a different way: Field-first, Instance-second.
 
     """
-
-    class DataSetIter(object):
-        def __init__(self, data_set, idx=-1, **fields):
-            self.data_set = data_set
-            self.idx = idx
-            self.fields = fields
-
-        def __next__(self):
-            self.idx += 1
-            if self.idx >= len(self.data_set):
-                raise StopIteration
-            # this returns a copy
-            return self.data_set[self.idx]
-
-        def __repr__(self):
-            return "\n".join(['{}: {}'.format(name, repr(self.data_set[name][self.idx])) for name
-                              in self.data_set.get_fields().keys()])
-
     def __init__(self, data=None):
         """
 
@@ -72,7 +56,27 @@ class DataSet(object):
         return item in self.field_arrays
 
     def __iter__(self):
-        return self.DataSetIter(self)
+        def iter_func():
+            for idx in range(len(self)):
+                yield self[idx]
+        return iter_func()
+
+    def _inner_iter(self):
+        class Iter_ptr:
+            def __init__(self, dataset, idx):
+                self.dataset = dataset
+                self.idx = idx
+            def __getitem__(self, item):
+                assert self.idx < len(self.dataset), "index:{} out of range".format(self.idx)
+                assert item in self.dataset.field_arrays, "no such field:{} in instance {}".format(item, self.dataset[self.idx])
+                return self.dataset.field_arrays[item][self.idx]
+            def __repr__(self):
+                return self.dataset[self.idx].__repr__()
+
+        def inner_iter_func():
+            for idx in range(len(self)):
+                yield Iter_ptr(self, idx)
+        return inner_iter_func()
 
     def __getitem__(self, idx):
         """Fetch Instance(s) at the `idx` position(s) in the dataset.
@@ -110,6 +114,15 @@ class DataSet(object):
         field = iter(self.field_arrays.values()).__next__()
         return len(field)
 
+    def __inner_repr__(self):
+        if len(self) < 20:
+            return ",\n".join([ins.__repr__() for ins in self])
+        else:
+            return self[:5].__inner_repr__() + "\n...\n" + self[-5:].__inner_repr__()
+
+    def __repr__(self):
+        return "DataSet(" + self.__inner_repr__() + ")"
+
     def append(self, ins):
         """Add an instance to the DataSet.
         If the DataSet is not empty, the instance must have the same field names as the rest instances in the DataSet.
@@ -226,7 +239,10 @@ class DataSet(object):
             (2) is_target: boolean, will be ignored if new_field is None. If True, the new field will be as target.
         :return results: if new_field_name is not passed, returned values of the function over all instances.
         """
-        results = [func(ins) for ins in self]
+        results = [func(ins) for ins in self._inner_iter()]
+        if len(list(filter(lambda x: x is not None, results)))==0: # all None
+            raise ValueError("{} always return None.".format(get_func_signature(func=func)))
+
         extra_param = {}
         if 'is_input' in kwargs:
             extra_param['is_input'] = kwargs['is_input']
@@ -250,7 +266,7 @@ class DataSet(object):
             return results
 
     def drop(self, func):
-        results = [ins for ins in self if not func(ins)]
+        results = [ins for ins in self._inner_iter() if not func(ins)]
         for name, old_field in self.field_arrays.items():
             self.field_arrays[name].content = [ins[name] for ins in results]
 
@@ -317,3 +333,12 @@ class DataSet(object):
                 for header, content in zip(headers, contents):
                     _dict[header].append(content)
         return cls(_dict)
+
+    def save(self, path):
+        with open(path, 'wb') as f:
+            pickle.dump(self, f)
+
+    @staticmethod
+    def load(self, path):
+        with open(path, 'rb') as f:
+            return pickle.load(f)
diff --git a/fastNLP/core/instance.py b/fastNLP/core/instance.py
index 9dfe8fb8..dc65fa82 100644
--- a/fastNLP/core/instance.py
+++ b/fastNLP/core/instance.py
@@ -1,5 +1,3 @@
-
-
 class Instance(object):
     """An Instance is an example of data. It is the collection of Fields.
 
@@ -33,4 +31,5 @@ class Instance(object):
         return self.add_field(name, field)
 
     def __repr__(self):
-        return self.fields.__repr__()
+        return "{" + ",\n".join(
+            "\'" + field_name + "\': " + str(self.fields[field_name]) for field_name in self.fields) + "}"
diff --git a/fastNLP/core/losses.py b/fastNLP/core/losses.py
index dce568bd..f2fb16d0 100644
--- a/fastNLP/core/losses.py
+++ b/fastNLP/core/losses.py
@@ -70,13 +70,23 @@ class LossBase(object):
             raise NameError(f"Delete `*{func_spect.varargs}` in {get_func_signature(self.get_loss)}(Do not use "
                             f"positional argument.).")
 
-    def __call__(self, output_dict, target_dict, force_check=False):
+    def _fast_param_map(self, pred_dict, target_dict):
+        if len(self.param_map) == 2 and len(pred_dict) == 1 and len(target_dict) == 1:
+            return tuple(pred_dict.values())[0], tuple(target_dict.values())[0]
+        return None
+
+    def __call__(self, pred_dict, target_dict, check=False):
         """
-        :param output_dict: A dict from forward function of the network.
+        :param pred_dict: A dict from forward function of the network.
         :param target_dict: A dict from DataSet.batch_y.
-        :param force_check: Boolean. Force to check the mapping functions when it is running.
+        :param check: Boolean. Force to check the mapping functions when it is running.
         :return:
         """
+        fast_param = self._fast_param_map(pred_dict, target_dict)
+        if fast_param is not None:
+            loss = self.get_loss(*fast_param)
+            return loss
+
         args, defaults, defaults_val, varargs, kwargs = _get_arg_list(self.get_loss)
         if varargs is not None:
             raise RuntimeError(
@@ -88,7 +98,8 @@ class LossBase(object):
             raise RuntimeError(
                 f"There is not any param in function{get_func_signature(self.get_loss)}"
             )
-        self._checked = self._checked and not force_check
+
+        self._checked = self._checked and not check
         if not self._checked:
             for keys in args:
                 if keys not in param_map:
@@ -105,12 +116,12 @@ class LossBase(object):
         duplicated = []
         missing = []
         if not self._checked:
-            for keys, val in output_dict.items():
+            for keys, val in pred_dict.items():
                 if keys in target_dict.keys():
                     duplicated.append(keys)
 
         param_val_dict = {}
-        for keys, val in output_dict.items():
+        for keys, val in pred_dict.items():
             param_val_dict.update({keys: val})
         for keys, val in target_dict.items():
             param_val_dict.update({keys: val})
@@ -131,7 +142,6 @@ class LossBase(object):
 
         param_map_val = _map_args(reversed_param_map, **param_val_dict)
         param_value = _build_args(self.get_loss, **param_map_val)
-
         loss = self.get_loss(**param_value)
 
         if not (isinstance(loss, torch.Tensor) and len(loss.size()) == 0):
@@ -158,29 +168,31 @@ class LossFunc(LossBase):
 
 
 class CrossEntropyLoss(LossBase):
-    def __init__(self, input=None, target=None):
+    def __init__(self, pred=None, target=None):
         super(CrossEntropyLoss, self).__init__()
         self.get_loss = F.cross_entropy
-        self._init_param_map(input=input, target=target)
+        self._init_param_map(input=pred, target=target)
 
 
 class L1Loss(LossBase):
-    def __init__(self):
+    def __init__(self, pred=None, target=None):
         super(L1Loss, self).__init__()
         self.get_loss = F.l1_loss
+        self._init_param_map(input=pred, target=target)
 
 
 class BCELoss(LossBase):
-    def __init__(self, input=None, target=None):
+    def __init__(self, pred=None, target=None):
         super(BCELoss, self).__init__()
         self.get_loss = F.binary_cross_entropy
-        self._init_param_map(input=input, target=target)
+        self._init_param_map(input=pred, target=target)
 
 
 class NLLLoss(LossBase):
-    def __init__(self):
+    def __init__(self, pred=None, target=None):
         super(NLLLoss, self).__init__()
         self.get_loss = F.nll_loss
+        self._init_param_map(input=pred, target=target)
 
 
 class LossInForward(LossBase):
@@ -199,10 +211,11 @@ class LossInForward(LossBase):
                                  all_needed=[],
                                  varargs=[])
             raise CheckError(check_res=check_res, func_signature=get_func_signature(self.get_loss))
+        return kwargs[self.loss_key]
 
-    def __call__(self, output_dict, predict_dict, force_check=False):
+    def __call__(self, pred_dict, target_dict, check=False):
 
-        loss = self.get_loss(**output_dict)
+        loss = self.get_loss(**pred_dict)
 
         if not (isinstance(loss, torch.Tensor) and len(loss.size()) == 0):
             if not isinstance(loss, torch.Tensor):
diff --git a/fastNLP/core/metrics.py b/fastNLP/core/metrics.py
index b1fc110b..d83c4022 100644
--- a/fastNLP/core/metrics.py
+++ b/fastNLP/core/metrics.py
@@ -1,4 +1,3 @@
-
 import inspect
 import warnings
 from collections import defaultdict
@@ -7,11 +6,12 @@ import numpy as np
 import torch
 
 from fastNLP.core.utils import CheckError
+from fastNLP.core.utils import CheckRes
 from fastNLP.core.utils import _build_args
 from fastNLP.core.utils import _check_arg_dict_list
 from fastNLP.core.utils import get_func_signature
 from fastNLP.core.utils import seq_lens_to_masks
-from fastNLP.core.utils import CheckRes
+
 
 class MetricBase(object):
     def __init__(self):
@@ -59,9 +59,10 @@ class MetricBase(object):
         func_args = [arg for arg in func_spect.args if arg != 'self']
         for func_param, input_param in self.param_map.items():
             if func_param not in func_args:
-                raise NameError(f"Parameter `{func_param}` is not in {get_func_signature(self.evaluate)}. Please check the "
-                                f"initialization parameters, or change the signature of"
-                                f" {get_func_signature(self.evaluate)}.")
+                raise NameError(
+                    f"Parameter `{func_param}` is not in {get_func_signature(self.evaluate)}. Please check the "
+                    f"initialization parameters, or change the signature of"
+                    f" {get_func_signature(self.evaluate)}.")
 
         # evaluate should not have varargs.
         if func_spect.varargs:
@@ -71,7 +72,7 @@ class MetricBase(object):
     def get_metric(self, reset=True):
         raise NotImplemented
 
-    def _fast_call_evaluate(self, pred_dict, target_dict):
+    def _fast_param_map(self, pred_dict, target_dict):
         """
 
         Only used as inner function. When the pred_dict, target is unequivocal. Don't need users to pass key_map.
@@ -80,7 +81,9 @@ class MetricBase(object):
         :param target_dict:
         :return: boolean, whether to go on codes in self.__call__(). When False, don't go on.
         """
-        return False
+        if len(self.param_map) == 2 and len(pred_dict) == 1 and len(target_dict) == 1:
+            return pred_dict.values[0] and target_dict.values[0]
+        return None
 
     def __call__(self, pred_dict, target_dict, check=False):
         """
@@ -103,13 +106,15 @@ class MetricBase(object):
             raise TypeError(f"{self.__class__.__name__}.evaluate has to be callable, not {type(self.evaluate)}.")
 
         if not check:
-            if self._fast_call_evaluate(pred_dict=pred_dict, target_dict=target_dict):
+            fast_param = self._fast_param_map(pred_dict=pred_dict, target_dict=target_dict)
+            if fast_param is not None:
+                self.evaluate(*fast_param)
                 return
 
         if not self._checked:
             # 1. check consistence between signature and param_map
             func_spect = inspect.getfullargspec(self.evaluate)
-            func_args = set([arg for arg in func_spect.args if arg!='self'])
+            func_args = set([arg for arg in func_spect.args if arg != 'self'])
             for func_arg, input_arg in self.param_map.items():
                 if func_arg not in func_args:
                     raise NameError(f"`{func_arg}` not in {get_func_signature(self.evaluate)}.")
@@ -117,7 +122,7 @@ class MetricBase(object):
             # 2. only part of the param_map are passed, left are not
             for arg in func_args:
                 if arg not in self.param_map:
-                    self.param_map[arg] = arg #This param does not need mapping.
+                    self.param_map[arg] = arg  # This param does not need mapping.
             self._evaluate_args = func_args
             self._reverse_param_map = {input_arg: func_arg for func_arg, input_arg in self.param_map.items()}
 
@@ -149,14 +154,14 @@ class MetricBase(object):
             replaced_missing = list(missing)
             for idx, func_arg in enumerate(missing):
                 replaced_missing[idx] = f"{self.param_map[func_arg]}" + f"(assign to `{func_arg}` " \
-                                                                   f"in `{self.__class__.__name__}`)"
+                                                                        f"in `{self.__class__.__name__}`)"
 
             check_res = CheckRes(missing=replaced_missing,
-                                unused=check_res.unused,
-                                duplicated=duplicated,
-                                required=check_res.required,
-                                all_needed=check_res.all_needed,
-                                varargs=check_res.varargs)
+                                 unused=check_res.unused,
+                                 duplicated=duplicated,
+                                 required=check_res.required,
+                                 all_needed=check_res.all_needed,
+                                 varargs=check_res.varargs)
 
             if check_res.missing or check_res.duplicated or check_res.varargs:
                 raise CheckError(check_res=check_res,
@@ -168,6 +173,7 @@ class MetricBase(object):
 
         return
 
+
 class AccuracyMetric(MetricBase):
     def __init__(self, pred=None, target=None, masks=None, seq_lens=None):
         super().__init__()
@@ -187,7 +193,7 @@ class AccuracyMetric(MetricBase):
         :param target_dict:
         :return: boolean, whether to go on codes in self.__call__(). When False, don't go on.
         """
-        if len(pred_dict)==1 and len(target_dict)==1:
+        if len(pred_dict) == 1 and len(target_dict) == 1:
             pred = list(pred_dict.values())[0]
             target = list(target_dict.values())[0]
             self.evaluate(pred=pred, target=target)
@@ -207,7 +213,7 @@ class AccuracyMetric(MetricBase):
                 None, None, torch.Size([B], torch.Size([B]). ignored if masks are provided.
         :return: dict({'acc': float})
         """
-        #TODO 这里报错需要更改，因为pred是啥用户并不知道。需要告知用户真实的value
+        # TODO 这里报错需要更改，因为pred是啥用户并不知道。需要告知用户真实的value
         if not isinstance(pred, torch.Tensor):
             raise TypeError(f"`pred` in {get_func_signature(self.evaluate)} must be torch.Tensor,"
                             f"got {type(pred)}.")
@@ -220,14 +226,14 @@ class AccuracyMetric(MetricBase):
                             f"got {type(masks)}.")
         elif seq_lens is not None and not isinstance(seq_lens, torch.Tensor):
             raise TypeError(f"`seq_lens` in {get_func_signature(self.evaluate)} must be torch.Tensor,"
-                                f"got {type(seq_lens)}.")
+                            f"got {type(seq_lens)}.")
 
         if masks is None and seq_lens is not None:
             masks = seq_lens_to_masks(seq_lens=seq_lens, float=True)
 
-        if pred.size()==target.size():
+        if pred.size() == target.size():
             pass
-        elif len(pred.size())==len(target.size())+1:
+        elif len(pred.size()) == len(target.size()) + 1:
             pred = pred.argmax(dim=-1)
         else:
             raise RuntimeError(f"In {get_func_signature(self.evaluate)}, when pred have "
@@ -241,18 +247,17 @@ class AccuracyMetric(MetricBase):
             self.acc_count += torch.sum(torch.eq(pred, target).float() * masks.float()).item()
             self.total += torch.sum(masks.float()).item()
         else:
-            self.acc_count +=  torch.sum(torch.eq(pred, target).float()).item()
+            self.acc_count += torch.sum(torch.eq(pred, target).float()).item()
             self.total += np.prod(list(pred.size()))
 
     def get_metric(self, reset=True):
-        evaluate_result = {'acc': round(self.acc_count/self.total, 6)}
+        evaluate_result = {'acc': round(self.acc_count / self.total, 6)}
         if reset:
             self.acc_count = 0
             self.total = 0
         return evaluate_result
 
 
-
 def _prepare_metrics(metrics):
     """
 
@@ -274,7 +279,8 @@ def _prepare_metrics(metrics):
                         raise TypeError(f"{metric_name}.get_metric must be callable, got {type(metric.get_metric)}.")
                     _metrics.append(metric)
                 else:
-                    raise TypeError(f"The type of metric in metrics must be `fastNLP.MetricBase`, not `{type(metric)}`.")
+                    raise TypeError(
+                        f"The type of metric in metrics must be `fastNLP.MetricBase`, not `{type(metric)}`.")
         elif isinstance(metrics, MetricBase):
             _metrics = [metrics]
         else:
@@ -296,6 +302,7 @@ class Evaluator(object):
         """
         raise NotImplementedError
 
+
 class ClassifyEvaluator(Evaluator):
     def __init__(self):
         super(ClassifyEvaluator, self).__init__()
@@ -331,6 +338,7 @@ class SeqLabelEvaluator(Evaluator):
         accuracy = total_correct / total_count
         return {"accuracy": float(accuracy)}
 
+
 class SeqLabelEvaluator2(Evaluator):
     # 上面的evaluator应该是错误的
     def __init__(self, seq_lens_field_name='word_seq_origin_len'):
@@ -363,7 +371,7 @@ class SeqLabelEvaluator2(Evaluator):
                     if x_i in self.end_tagidx_set:
                         truth_count += 1
                         for j in range(start, idx_i + 1):
-                            if y_[j]!=x_[j]:
+                            if y_[j] != x_[j]:
                                 flag = False
                                 break
                         if flag:
@@ -376,8 +384,7 @@ class SeqLabelEvaluator2(Evaluator):
         R = corr_count / (float(truth_count) + 1e-6)
         F = 2 * P * R / (P + R + 1e-6)
 
-        return {"P": P, 'R':R, 'F': F}
-
+        return {"P": P, 'R': R, 'F': F}
 
 
 class SNLIEvaluator(Evaluator):
@@ -559,10 +566,6 @@ def f1_score(y_true, y_pred, labels=None, pos_label=1, average='binary'):
     return 2 * precision * recall / (precision + recall) if (precision + recall) > 0 else 0
 
 
-def classification_report(y_true, y_pred, labels=None, target_names=None, digits=2):
-    raise NotImplementedError
-
-
 def accuracy_topk(y_true, y_prob, k=1):
     """Compute accuracy of y_true matching top-k probable
     labels in y_prob.
diff --git a/fastNLP/core/optimizer.py b/fastNLP/core/optimizer.py
index 5075fa02..469c5632 100644
--- a/fastNLP/core/optimizer.py
+++ b/fastNLP/core/optimizer.py
@@ -4,40 +4,13 @@ import torch
 class Optimizer(object):
     def __init__(self, model_params, **kwargs):
         if model_params is not None and not hasattr(model_params, "__next__"):
-            raise RuntimeError("model parameters should be a generator, rather than {}".format(type(model_params)))
+            raise RuntimeError("model parameters should be a generator, rather than {}.".format(type(model_params)))
         self.model_params = model_params
         self.settings = kwargs
 
 
 class SGD(Optimizer):
-    def __init__(self, *args, **kwargs):
-        model_params, lr, momentum = None, 0.01, 0.9
-        if len(args) == 0 and len(kwargs) == 0:
-            # SGD()
-            pass
-        elif len(args) == 1 and len(kwargs) == 0:
-            if isinstance(args[0], float) or isinstance(args[0], int):
-                # SGD(0.001)
-                lr = args[0]
-            elif hasattr(args[0], "__next__"):
-                # SGD(model.parameters())  args[0] is a generator
-                model_params = args[0]
-            else:
-                raise RuntimeError("Not supported type {}.".format(type(args[0])))
-        elif 2 >= len(kwargs) > 0 and len(args) <= 1:
-            # SGD(lr=0.01), SGD(lr=0.01, momentum=0.9), SGD(model.parameters(), lr=0.1, momentum=0.9)
-            if len(args) == 1:
-                if hasattr(args[0], "__next__"):
-                    model_params = args[0]
-                else:
-                    raise RuntimeError("Not supported type {}.".format(type(args[0])))
-            if not all(key in ("lr", "momentum") for key in kwargs):
-                raise RuntimeError("Invalid SGD arguments. Expect {}, got {}.".format(("lr", "momentum"), kwargs))
-            lr = kwargs.get("lr", 0.01)
-            momentum = kwargs.get("momentum", 0.9)
-        else:
-            raise RuntimeError("SGD only accept 0 or 1 sequential argument, but got {}: {}".format(len(args), args))
-
+    def __init__(self, model_params=None, lr=0.01, momentum=0):
         super(SGD, self).__init__(model_params, lr=lr, momentum=momentum)
 
     def construct_from_pytorch(self, model_params):
@@ -49,30 +22,7 @@ class SGD(Optimizer):
 
 
 class Adam(Optimizer):
-    def __init__(self, *args, **kwargs):
-        model_params, lr, weight_decay = None, 0.01, 0.9
-        if len(args) == 0 and len(kwargs) == 0:
-            pass
-        elif len(args) == 1 and len(kwargs) == 0:
-            if isinstance(args[0], float) or isinstance(args[0], int):
-                lr = args[0]
-            elif hasattr(args[0], "__next__"):
-                model_params = args[0]
-            else:
-                raise RuntimeError("Not supported type {}.".format(type(args[0])))
-        elif 2 >= len(kwargs) > 0 and len(args) <= 1:
-            if len(args) == 1:
-                if hasattr(args[0], "__next__"):
-                    model_params = args[0]
-                else:
-                    raise RuntimeError("Not supported type {}.".format(type(args[0])))
-            if not all(key in ("lr", "weight_decay") for key in kwargs):
-                raise RuntimeError("Invalid Adam arguments. Expect {}, got {}.".format(("lr", "weight_decay"), kwargs))
-            lr = kwargs.get("lr", 0.01)
-            weight_decay = kwargs.get("weight_decay", 0.9)
-        else:
-            raise RuntimeError("Adam only accept 0 or 1 sequential argument, but got {}: {}".format(len(args), args))
-
+    def __init__(self, model_params=None, lr=0.01, weight_decay=0):
         super(Adam, self).__init__(model_params, lr=lr, weight_decay=weight_decay)
 
     def construct_from_pytorch(self, model_params):
diff --git a/fastNLP/core/trainer.py b/fastNLP/core/trainer.py
index 95749c73..57c79369 100644
--- a/fastNLP/core/trainer.py
+++ b/fastNLP/core/trainer.py
@@ -1,6 +1,7 @@
 import os
 import time
 from datetime import datetime
+from datetime import timedelta
 from tqdm import tqdm
 
 import torch
@@ -22,17 +23,16 @@ from fastNLP.core.utils import _check_forward_error
 from fastNLP.core.utils import _check_loss_evaluate
 from fastNLP.core.utils import _move_dict_value_to_device
 from fastNLP.core.utils import get_func_signature
-
+from fastNLP.core.utils import _relocate_pbar
 
 class Trainer(object):
     """Main Training Loop
 
     """
-
     def __init__(self, train_data, model, losser=None, metrics=None, n_epochs=3, batch_size=32, update_every=50,
                  validate_every=-1, dev_data=None, use_cuda=False, save_path=None,
                  optimizer=Adam(lr=0.01, weight_decay=0), check_code_level=0,
-                 metric_key=None, sampler=RandomSampler()):
+                 metric_key=None, sampler=RandomSampler(), use_tqdm=True):
         """
 
         :param DataSet train_data: the training data
@@ -54,6 +54,7 @@ class Trainer(object):
                 ::
                     metric_key="-PPL"   # language model gets better as perplexity gets smaller
         :param sampler: method used to generate batch data.
+        :param use_tqdm: boolean, use tqdm to show train progress.
 
         """
         super(Trainer, self).__init__()
@@ -117,19 +118,23 @@ class Trainer(object):
         else:
             self.optimizer = optimizer.construct_from_pytorch(self.model.parameters())
 
+        self.use_tqdm = use_tqdm
+        if self.use_tqdm:
+            tester_verbose = 0
+        else:
+            tester_verbose = 1
+
         if self.dev_data is not None:
             self.tester = Tester(model=self.model,
                                  data=self.dev_data,
                                  metrics=self.metrics,
                                  batch_size=self.batch_size,
                                  use_cuda=self.use_cuda,
-                                 verbose=0)
+                                 verbose=tester_verbose)
 
         self.step = 0
         self.start_time = None  # start timestamp
 
-        # print(self.__dict__)
-
     def train(self):
         """Start Training.
 
@@ -155,8 +160,10 @@ class Trainer(object):
             else:
                 path = os.path.join(self.save_path, 'tensorboard_logs_{}'.format(self.start_time))
                 self._summary_writer = SummaryWriter(path)
-
-            self._tqdm_train()
+            if self.use_tqdm:
+                self._tqdm_train()
+            else:
+                self._print_train()
 
         finally:
             self._summary_writer.close()
@@ -196,31 +203,67 @@ class Trainer(object):
                         eval_res = self._do_validation()
                         eval_str = "Epoch {}/{}. Step:{}/{}. ".format(epoch, self.n_epochs, self.step, total_steps) + \
                                    self.tester._format_eval_results(eval_res)
-                        pbar = self._relocate_pbar(pbar, print_str=eval_str, total=total_steps, initial=self.step)
-                    time.sleep(0.1)
+                        pbar = _relocate_pbar(pbar, print_str=eval_str)
                 if self.validate_every < 0 and self.dev_data:
                     eval_res = self._do_validation()
                     eval_str = "Epoch {}/{}. Step:{}/{}. ".format(epoch, self.n_epochs, self.step, total_steps) + \
                                self.tester._format_eval_results(eval_res)
-                    pbar = self._relocate_pbar(pbar, print_str=eval_str, total=total_steps, initial=self.step)
+                    pbar = _relocate_pbar(pbar, print_str=eval_str)
                 if epoch!=self.n_epochs:
                     data_iterator = Batch(self.train_data, batch_size=self.batch_size, sampler=self.sampler,
                                           as_numpy=False)
             pbar.close()
 
-    def _relocate_pbar(self, pbar, total, initial, print_str=None):
-        postfix = pbar.postfix
-        desc = pbar.desc
-        pbar.close()
-        avg_time = pbar.avg_time
-        start_t = pbar.start_t
-        if print_str:
-            print(print_str)
-        pbar = tqdm(total=total, postfix=postfix, desc=desc, leave=False, initial=initial, dynamic_ncols=True)
-        pbar.start_t = start_t
-        pbar.avg_time = avg_time
-        pbar.sp(pbar.__repr__())
-        return pbar
+
+    def _print_train(self):
+        """
+
+        :param data_iterator:
+        :param model:
+        :param epoch:
+        :param start:
+        :return:
+        """
+        epoch = 1
+        start = time.time()
+        while epoch <= self.n_epochs:
+
+            data_iterator = Batch(self.train_data, batch_size=self.batch_size, sampler=self.sampler,
+                                  as_numpy=False)
+
+            for batch_x, batch_y in data_iterator:
+                # TODO 这里可能会遇到问题，万一用户在model内部修改了prediction的device就会有问题
+                _move_dict_value_to_device(batch_x, batch_y, device=self._model_device)
+                prediction = self._data_forward(self.model, batch_x)
+                loss = self._compute_loss(prediction, batch_y)
+                self._grad_backward(loss)
+                self._update()
+                self._summary_writer.add_scalar("loss", loss.item(), global_step=self.step)
+                for name, param in self.model.named_parameters():
+                    if param.requires_grad:
+                        self._summary_writer.add_scalar(name + "_mean", param.mean(), global_step=self.step)
+                        # self._summary_writer.add_scalar(name + "_std", param.std(), global_step=self.step)
+                        # self._summary_writer.add_scalar(name + "_grad_sum", param.sum(), global_step=self.step)
+                if self.print_every > 0 and self.step % self.print_every == 0:
+                    end = time.time()
+                    diff = timedelta(seconds=round(end - start))
+                    print_output = "[epoch: {:>3} step: {:>4}] train loss: {:>4.6} time:  {}".format(
+                        epoch, self.step, loss.data, diff)
+                    print(print_output)
+
+                if (self.validate_every > 0 and self.step % self.validate_every == 0 and
+                        self.dev_data is not None):
+                    self._do_validation()
+
+                self.step += 1
+
+            # validate_every override validation at end of epochs
+            if self.dev_data and self.validate_every <= 0:
+                self._do_validation()
+            epoch += 1
+
+
+
 
     def _do_validation(self):
         res = self.tester.test()
diff --git a/fastNLP/core/utils.py b/fastNLP/core/utils.py
index 6d11686c..9fc091a7 100644
--- a/fastNLP/core/utils.py
+++ b/fastNLP/core/utils.py
@@ -7,9 +7,12 @@ from collections import namedtuple
 
 import numpy as np
 import torch
+from tqdm import tqdm
 
 CheckRes = namedtuple('CheckRes', ['missing', 'unused', 'duplicated', 'required', 'all_needed',
                                    'varargs'], verbose=False)
+
+
 def save_pickle(obj, pickle_path, file_name):
     """Save an object into a pickle file.
 
@@ -53,6 +56,7 @@ def pickle_exist(pickle_path, pickle_name):
     else:
         return False
 
+
 def _build_args(func, **kwargs):
     spect = inspect.getfullargspec(func)
     if spect.varkw is not None:
@@ -108,7 +112,7 @@ def _check_arg_dict_list(func, args):
     assert callable(func) and isinstance(arg_dict_list, (list, tuple))
     assert len(arg_dict_list) > 0 and isinstance(arg_dict_list[0], dict)
     spect = inspect.getfullargspec(func)
-    all_args = set([arg for arg in spect.args if arg!='self'])
+    all_args = set([arg for arg in spect.args if arg != 'self'])
     defaults = []
     if spect.defaults is not None:
         defaults = [arg for arg in spect.defaults]
@@ -130,6 +134,7 @@ def _check_arg_dict_list(func, args):
                     all_needed=list(all_args),
                     varargs=varargs)
 
+
 def get_func_signature(func):
     """
 
@@ -153,7 +158,7 @@ def get_func_signature(func):
         class_name = func.__self__.__class__.__name__
         signature = inspect.signature(func)
         signature_str = str(signature)
-        if len(signature_str)>2:
+        if len(signature_str) > 2:
             _self = '(self, '
         else:
             _self = '(self'
@@ -176,12 +181,13 @@ def _is_function_or_method(func):
         return False
     return True
 
+
 def _check_function_or_method(func):
     if not _is_function_or_method(func):
         raise TypeError(f"{type(func)} is not a method or function.")
 
 
-def _move_dict_value_to_device(*args, device:torch.device):
+def _move_dict_value_to_device(*args, device: torch.device):
     """
 
     move data to model's device, element in *args should be dict. This is a inplace change.
@@ -206,7 +212,8 @@ class CheckError(Exception):
 
     CheckError. Used in losses.LossBase, metrics.MetricBase.
     """
-    def __init__(self, check_res:CheckRes, func_signature:str):
+
+    def __init__(self, check_res: CheckRes, func_signature: str):
         errs = [f'The following problems occurred when calling `{func_signature}`']
 
         if check_res.varargs:
@@ -228,8 +235,9 @@ IGNORE_CHECK_LEVEL = 0
 WARNING_CHECK_LEVEL = 1
 STRICT_CHECK_LEVEL = 2
 
-def _check_loss_evaluate(prev_func_signature:str, func_signature:str, check_res:CheckRes,
-                         pred_dict:dict, target_dict:dict, dataset, check_level=0):
+
+def _check_loss_evaluate(prev_func_signature: str, func_signature: str, check_res: CheckRes,
+                         pred_dict: dict, target_dict: dict, dataset, check_level=0):
     errs = []
     unuseds = []
     _unused_field = []
@@ -268,8 +276,8 @@ def _check_loss_evaluate(prev_func_signature:str, func_signature:str, check_res:
                                f"target is {list(target_dict.keys())}).")
         if _miss_out_dataset:
             _tmp = (f"You might need to provide {_miss_out_dataset} in DataSet and set it as target(Right now "
-                               f"target is {list(target_dict.keys())}) or output it "
-                               f"in {prev_func_signature}(Right now it outputs {list(pred_dict.keys())}).")
+                    f"target is {list(target_dict.keys())}) or output it "
+                    f"in {prev_func_signature}(Right now it outputs {list(pred_dict.keys())}).")
             if _unused_field:
                 _tmp += f"You can use DataSet.rename_field() to rename the field in `unused field:`. "
             suggestions.append(_tmp)
@@ -277,15 +285,15 @@ def _check_loss_evaluate(prev_func_signature:str, func_signature:str, check_res:
     if check_res.duplicated:
         errs.append(f"\tduplicated param: {check_res.duplicated}.")
         suggestions.append(f"Delete {check_res.duplicated} in the output of "
-                    f"{prev_func_signature} or do not set {check_res.duplicated} as targets. ")
+                           f"{prev_func_signature} or do not set {check_res.duplicated} as targets. ")
 
     if check_level == STRICT_CHECK_LEVEL:
         errs.extend(unuseds)
 
-    if len(errs)>0:
+    if len(errs) > 0:
         errs.insert(0, f'The following problems occurred when calling {func_signature}')
         sugg_str = ""
-        if len(suggestions)>1:
+        if len(suggestions) > 1:
             for idx, sugg in enumerate(suggestions):
                 sugg_str += f'({idx+1}). {sugg}'
         else:
@@ -332,10 +340,10 @@ def _check_forward_error(forward_func, batch_x, dataset, check_level):
         if check_level == STRICT_CHECK_LEVEL:
             errs.extend(_unused)
 
-    if len(errs)>0:
+    if len(errs) > 0:
         errs.insert(0, f'The following problems occurred when calling {func_signature}')
         sugg_str = ""
-        if len(suggestions)>1:
+        if len(suggestions) > 1:
             for idx, sugg in enumerate(suggestions):
                 sugg_str += f'({idx+1}). {sugg}'
         else:
@@ -357,11 +365,11 @@ def seq_lens_to_masks(seq_lens, float=True):
     :return: list, np.ndarray or torch.Tensor, shape will be (B, max_length)
     """
     if isinstance(seq_lens, np.ndarray):
-        assert len(np.shape(seq_lens))==1, f"seq_lens can only have one dimension, got {len(np.shape(seq_lens))}."
+        assert len(np.shape(seq_lens)) == 1, f"seq_lens can only have one dimension, got {len(np.shape(seq_lens))}."
         assert seq_lens.dtype in (int, np.int32, np.int64), f"seq_lens can only be integer, not {seq_lens.dtype}."
         raise NotImplemented
     elif isinstance(seq_lens, torch.LongTensor):
-        assert len(seq_lens.size())==1, f"seq_lens can only have one dimension, got {len(seq_lens.size())==1}."
+        assert len(seq_lens.size()) == 1, f"seq_lens can only have one dimension, got {len(seq_lens.size())==1}."
         batch_size = seq_lens.size(0)
         max_len = seq_lens.max()
         indexes = torch.arange(max_len).view(1, -1).repeat(batch_size, 1).to(seq_lens.device)
@@ -376,3 +384,54 @@ def seq_lens_to_masks(seq_lens, float=True):
     else:
         raise NotImplemented
 
+
+def seq_mask(seq_len, max_len):
+    """Create sequence mask.
+
+    :param seq_len: list or torch.Tensor, the lengths of sequences in a batch.
+    :param max_len: int, the maximum sequence length in a batch.
+    :return mask: torch.LongTensor, [batch_size, max_len]
+
+    """
+    if not isinstance(seq_len, torch.Tensor):
+        seq_len = torch.LongTensor(seq_len)
+    seq_len = seq_len.view(-1, 1).long()   # [batch_size, 1]
+    seq_range = torch.arange(start=0, end=max_len, dtype=torch.long, device=seq_len.device).view(1, -1) # [1, max_len]
+    return torch.gt(seq_len, seq_range) # [batch_size, max_len]
+
+
+def _relocate_pbar(pbar:tqdm, print_str:str):
+    """
+
+    When using tqdm, you cannot print. If you print, the tqdm will duplicate. By using this function, print_str will
+        show above tqdm.
+    :param pbar: tqdm
+    :param print_str:
+    :return:
+    """
+
+    params = ['desc', 'total', 'leave', 'file', 'ncols', 'mininterval', 'maxinterval', 'miniters', 'ascii', 'disable',
+     'unit', 'unit_scale', 'dynamic_ncols', 'smoothing', 'bar_format', 'initial', 'position', 'postfix', 'unit_divisor',
+     'gui']
+
+    attr_map = {'file': 'fp', 'initial':'n', 'position':'pos'}
+
+    param_dict = {}
+    for param in params:
+        attr_name = param
+        if param in attr_map:
+            attr_name = attr_map[param]
+        value = getattr(pbar, attr_name)
+        if attr_name == 'pos':
+            value = abs(value)
+        param_dict[param] = value
+
+    pbar.close()
+    avg_time = pbar.avg_time
+    start_t = pbar.start_t
+    print(print_str)
+    pbar = tqdm(**param_dict)
+    pbar.start_t = start_t
+    pbar.avg_time = avg_time
+    pbar.sp(pbar.__repr__())
+    return pbar
\ No newline at end of file
diff --git a/fastNLP/io/embed_loader.py b/fastNLP/io/embed_loader.py
index 6e557c2b..779b7fd0 100644
--- a/fastNLP/io/embed_loader.py
+++ b/fastNLP/io/embed_loader.py
@@ -105,9 +105,9 @@ class EmbedLoader(BaseLoader):
 
         if np.sum(hit_flags) < len(vocab):
             # some words from vocab are missing in pre-trained embedding
-            # we normally sample them
+            # we normally sample each dimension
             vocab_embed = embedding_matrix[np.where(hit_flags)]
-            mean, cov = vocab_embed.mean(axis=0), np.cov(vocab_embed.T)
-            sampled_vectors = np.random.multivariate_normal(mean, cov, size=(len(vocab) - np.sum(hit_flags),))
+            sampled_vectors = np.random.normal(vocab_embed.mean(axis=0), vocab_embed.std(axis=0),
+                                               size=(len(vocab) - np.sum(hit_flags), emb_dim))
             embedding_matrix[np.where(1 - hit_flags)] = sampled_vectors
         return embedding_matrix
diff --git a/fastNLP/modules/encoder/char_embedding.py b/fastNLP/modules/encoder/char_embedding.py
index 1ca3b5ba..249a73ad 100644
--- a/fastNLP/modules/encoder/char_embedding.py
+++ b/fastNLP/modules/encoder/char_embedding.py
@@ -43,7 +43,7 @@ class ConvCharEmbedding(nn.Module):
             # [batch_size*sent_length, feature_maps[i], 1, width - kernels[i] + 1]
             y = torch.squeeze(y, 2)
             # [batch_size*sent_length, feature_maps[i], width - kernels[i] + 1]
-            y = F.tanh(y)
+            y = torch.tanh(y)
             y, __ = torch.max(y, 2)
             # [batch_size*sent_length, feature_maps[i]]
             feats.append(y)
diff --git a/test/core/test_dataset.py b/test/core/test_dataset.py
index 786e7248..8ca2ed86 100644
--- a/test/core/test_dataset.py
+++ b/test/core/test_dataset.py
@@ -44,6 +44,9 @@ class TestDataSet(unittest.TestCase):
         self.assertEqual(dd.field_arrays["y"].content, [[1, 2, 3, 4]] * 10)
         self.assertEqual(dd.field_arrays["z"].content, [[5, 6]] * 10)
 
+        with self.assertRaises(RuntimeError):
+            dd.add_field("??", [[1, 2]] * 40)
+
     def test_delete_field(self):
         dd = DataSet()
         dd.add_field("x", [[1, 2, 3]] * 10)
@@ -65,8 +68,66 @@ class TestDataSet(unittest.TestCase):
         self.assertTrue(isinstance(sub_ds, DataSet))
         self.assertEqual(len(sub_ds), 10)
 
+    def test_get_item_error(self):
+        with self.assertRaises(RuntimeError):
+            ds = DataSet({"x": [[1, 2, 3, 4]] * 10, "y": [[5, 6]] * 10})
+            _ = ds[40:]
+
+        with self.assertRaises(KeyError):
+            ds = DataSet({"x": [[1, 2, 3, 4]] * 10, "y": [[5, 6]] * 10})
+            _ = ds["kom"]
+
+    def test_len_(self):
+        ds = DataSet({"x": [[1, 2, 3, 4]] * 40, "y": [[5, 6]] * 40})
+        self.assertEqual(len(ds), 40)
+
+        ds = DataSet()
+        self.assertEqual(len(ds), 0)
+
     def test_apply(self):
         ds = DataSet({"x": [[1, 2, 3, 4]] * 40, "y": [[5, 6]] * 40})
         ds.apply(lambda ins: ins["x"][::-1], new_field_name="rx")
         self.assertTrue("rx" in ds.field_arrays)
         self.assertEqual(ds.field_arrays["rx"].content[0], [4, 3, 2, 1])
+
+    def test_contains(self):
+        ds = DataSet({"x": [[1, 2, 3, 4]] * 40, "y": [[5, 6]] * 40})
+        self.assertTrue("x" in ds)
+        self.assertTrue("y" in ds)
+        self.assertFalse("z" in ds)
+
+    def test_rename_field(self):
+        ds = DataSet({"x": [[1, 2, 3, 4]] * 10, "y": [[5, 6]] * 10})
+        ds.rename_field("x", "xx")
+        self.assertTrue("xx" in ds)
+        self.assertFalse("x" in ds)
+
+        with self.assertRaises(KeyError):
+            ds.rename_field("yyy", "oo")
+
+    def test_input_target(self):
+        ds = DataSet({"x": [[1, 2, 3, 4]] * 10, "y": [[5, 6]] * 10})
+        ds.set_input("x")
+        ds.set_target("y")
+        self.assertTrue(ds.field_arrays["x"].is_input)
+        self.assertTrue(ds.field_arrays["y"].is_target)
+
+        with self.assertRaises(KeyError):
+            ds.set_input("xxx")
+        with self.assertRaises(KeyError):
+            ds.set_input("yyy")
+
+    def test_get_input_name(self):
+        ds = DataSet({"x": [[1, 2, 3, 4]] * 10, "y": [[5, 6]] * 10})
+        self.assertEqual(ds.get_input_name(), [_ for _ in ds.field_arrays if ds.field_arrays[_].is_input])
+
+    def test_get_target_name(self):
+        ds = DataSet({"x": [[1, 2, 3, 4]] * 10, "y": [[5, 6]] * 10})
+        self.assertEqual(ds.get_target_name(), [_ for _ in ds.field_arrays if ds.field_arrays[_].is_target])
+
+
+class TestDataSetIter(unittest.TestCase):
+    def test__repr__(self):
+        ds = DataSet({"x": [[1, 2, 3, 4]] * 10, "y": [[5, 6]] * 10})
+        for iter in ds:
+            self.assertEqual(iter.__repr__(), "{'x': [1, 2, 3, 4],\n'y': [5, 6]}")
diff --git a/test/core/test_instance.py b/test/core/test_instance.py
index abe6b7f7..1342ba2c 100644
--- a/test/core/test_instance.py
+++ b/test/core/test_instance.py
@@ -27,3 +27,9 @@ class TestCase(unittest.TestCase):
         self.assertEqual(ins["x"], [1, 2, 3])
         self.assertEqual(ins["y"], [4, 5, 6])
         self.assertEqual(ins["z"], [1, 1, 1])
+
+    def test_repr(self):
+        fields = {"x": [1, 2, 3], "y": [4, 5, 6], "z": [1, 1, 1]}
+        ins = Instance(**fields)
+        # simple print, that is enough.
+        print(ins)
diff --git a/test/core/test_loss.py b/test/core/test_loss.py
index 1124860b..9b77d0a1 100644
--- a/test/core/test_loss.py
+++ b/test/core/test_loss.py
@@ -271,40 +271,32 @@ class TestLoss(unittest.TestCase):
         loss3 = get_loss_3({'predict': predict}, {'truth': truth})
         assert loss1 == loss2 and loss1 == loss3
 
-        """
-        get_loss_4 = LossFunc(func4)
-        loss4 = get_loss_4({'a': 1, 'b': 3}, {})
-        print(loss4)
-        assert loss4 == (1 + 3) * 2
-
-        get_loss_5 = LossFunc(func4)
-        loss5 = get_loss_5({'a': 1, 'b': 3}, {'c': 4})
-        print(loss5)
-        assert loss5 == (1 + 3) * 4
-
-        get_loss_6 = LossFunc(func6)
-        loss6 = get_loss_6({'a': 1, 'b': 3}, {'c': 4})
-        print(loss6)
-        assert loss6 == (1 + 3) * 4
-
-        get_loss_7 = LossFunc(func6, c='cc')
-        loss7 = get_loss_7({'a': 1, 'b': 3}, {'cc': 4})
-        print(loss7)
-        assert loss7 == (1 + 3) * 4
-        """
-
 
 class TestLoss_v2(unittest.TestCase):
     def test_CrossEntropyLoss(self):
-        ce = loss.CrossEntropyLoss(input="my_predict", target="my_truth")
+        ce = loss.CrossEntropyLoss(pred="my_predict", target="my_truth")
         a = torch.randn(3, 5, requires_grad=False)
         b = torch.empty(3, dtype=torch.long).random_(5)
         ans = ce({"my_predict": a}, {"my_truth": b})
         self.assertEqual(ans, torch.nn.functional.cross_entropy(a, b))
 
     def test_BCELoss(self):
-        bce = loss.BCELoss(input="my_predict", target="my_truth")
+        bce = loss.BCELoss(pred="my_predict", target="my_truth")
         a = torch.sigmoid(torch.randn((3, 5), requires_grad=False))
         b = torch.randn((3, 5), requires_grad=False)
         ans = bce({"my_predict": a}, {"my_truth": b})
         self.assertEqual(ans, torch.nn.functional.binary_cross_entropy(a, b))
+
+    def test_L1Loss(self):
+        l1 = loss.L1Loss(pred="my_predict", target="my_truth")
+        a = torch.randn(3, 5, requires_grad=False)
+        b = torch.randn(3, 5)
+        ans = l1({"my_predict": a}, {"my_truth": b})
+        self.assertEqual(ans, torch.nn.functional.l1_loss(a, b))
+
+    def test_NLLLoss(self):
+        l1 = loss.NLLLoss(pred="my_predict", target="my_truth")
+        a = F.log_softmax(torch.randn(3, 5, requires_grad=False), dim=0)
+        b = torch.tensor([1, 0, 4])
+        ans = l1({"my_predict": a}, {"my_truth": b})
+        self.assertEqual(ans, torch.nn.functional.nll_loss(a, b))
diff --git a/test/core/test_optimizer.py b/test/core/test_optimizer.py
index ab18b9be..7b29b826 100644
--- a/test/core/test_optimizer.py
+++ b/test/core/test_optimizer.py
@@ -11,9 +11,6 @@ class TestOptim(unittest.TestCase):
         self.assertTrue("lr" in optim.__dict__["settings"])
         self.assertTrue("momentum" in optim.__dict__["settings"])
 
-        optim = SGD(0.001)
-        self.assertEqual(optim.__dict__["settings"]["lr"], 0.001)
-
         optim = SGD(lr=0.001)
         self.assertEqual(optim.__dict__["settings"]["lr"], 0.001)
 
@@ -25,17 +22,12 @@ class TestOptim(unittest.TestCase):
             _ = SGD("???")
         with self.assertRaises(RuntimeError):
             _ = SGD(0.001, lr=0.002)
-        with self.assertRaises(RuntimeError):
-            _ = SGD(lr=0.009, shit=9000)
 
     def test_Adam(self):
         optim = Adam(torch.nn.Linear(10, 3).parameters())
         self.assertTrue("lr" in optim.__dict__["settings"])
         self.assertTrue("weight_decay" in optim.__dict__["settings"])
 
-        optim = Adam(0.001)
-        self.assertEqual(optim.__dict__["settings"]["lr"], 0.001)
-
         optim = Adam(lr=0.001)
         self.assertEqual(optim.__dict__["settings"]["lr"], 0.001)
 
diff --git a/test/core/test_trainer.py b/test/core/test_trainer.py
index 5dce64a5..2975f39c 100644
--- a/test/core/test_trainer.py
+++ b/test/core/test_trainer.py
@@ -32,14 +32,14 @@ class TrainerTestGround(unittest.TestCase):
         model = NaiveClassifier(2, 1)
 
         trainer = Trainer(train_set, model,
-                          losser=BCELoss(input="predict", target="y"),
+                          losser=BCELoss(pred="predict", target="y"),
                           metrics=AccuracyMetric(pred="predict", target="y"),
                           n_epochs=10,
                           batch_size=32,
                           update_every=1,
-                          validate_every=-1,
+                          validate_every=10,
                           dev_data=dev_set,
-                          optimizer=SGD(0.1),
-                          check_code_level=2
-                          )
-        trainer.train()
+                          optimizer=SGD(lr=0.1),
+                          check_code_level=2,
+                          use_tqdm=True)
+        trainer.train()
\ No newline at end of file
diff --git a/test/io/test_embed_loader.py b/test/io/test_embed_loader.py
index fc1e7124..60e3710e 100644
--- a/test/io/test_embed_loader.py
+++ b/test/io/test_embed_loader.py
@@ -1,12 +1,12 @@
 import unittest
 
 from fastNLP.core.vocabulary import Vocabulary
+from fastNLP.io.embed_loader import EmbedLoader
 
 
 class TestEmbedLoader(unittest.TestCase):
     def test_case(self):
         vocab = Vocabulary()
         vocab.update(["the", "in", "I", "to", "of", "hahaha"])
-        # TODO: np.cov在linux上segment fault,原因未知
-        # embedding = EmbedLoader().fast_load_embedding(50, "../data_for_tests/glove.6B.50d_test.txt", vocab)
-        # self.assertEqual(tuple(embedding.shape), (len(vocab), 50))
+        embedding = EmbedLoader().fast_load_embedding(50, "test/data_for_tests/glove.6B.50d_test.txt", vocab)
+        self.assertEqual(tuple(embedding.shape), (len(vocab), 50))
diff --git a/test/test_tutorial.py b/test/test_tutorial.py
index fe6a9d86..f3648b4f 100644
--- a/test/test_tutorial.py
+++ b/test/test_tutorial.py
@@ -71,20 +71,16 @@ class TestTutorial(unittest.TestCase):
 
         # 实例化Trainer，传入模型和数据，进行训练
         copy_model = deepcopy(model)
-        overfit_trainer = Trainer(model=copy_model, train_data=test_data, dev_data=test_data,
-                                  losser=CrossEntropyLoss(input="output", target="label_seq"),
-                                  metrics=AccuracyMetric(pred="predict", target="label_seq"),
-                                  save_path="./save",
-                                  batch_size=4,
-                                  n_epochs=10)
+        overfit_trainer = Trainer(train_data=test_data, model=copy_model,
+                                  losser=CrossEntropyLoss(pred="output", target="label_seq"),
+                                  metrics=AccuracyMetric(pred="predict", target="label_seq"), n_epochs=10, batch_size=4,
+                                  dev_data=test_data, save_path="./save")
         overfit_trainer.train()
 
-        trainer = Trainer(model=model, train_data=train_data, dev_data=test_data,
-                          losser=CrossEntropyLoss(input="output", target="label_seq"),
-                          metrics=AccuracyMetric(pred="predict", target="label_seq"),
-                          save_path="./save",
-                          batch_size=4,
-                          n_epochs=10)
+        trainer = Trainer(train_data=train_data, model=model,
+                          losser=CrossEntropyLoss(pred="output", target="label_seq"),
+                          metrics=AccuracyMetric(pred="predict", target="label_seq"), n_epochs=10, batch_size=4,
+                          dev_data=test_data, save_path="./save")
         trainer.train()
         print('Train finished!')