However,behavioristic approach confronts a number of problems: (1)Language acquisition is not merely a matter of imitation,it is a matter of "creative construction". (2)A multiplicity of causes may lead to errors.Inter-lingual error is only one of them.In many cases,the occurrence of errors does not correspond to the prediction based on the results of contrastive analysis. All these undermine the validity of the behavioristic approach to errors.However, behavioristic approach confronts a number of problems: (1) Language acquisition is not merely a matter of imitation, it is a matter of ”creative construction”. (2) A multiplicity of causes may lead to errors. Inter-lingual error is only one of them. In many cases, the occurrence of errors does not correspond to the prediction based on the results of contrastive analysis. All these undermine the validity of the behavioristic approach to errors