At pre-assigned stage,which provide benifical input for pupil,assist them to know topics well and discern new words and phrase through learning importent linguistic knowlege for accomplish assignment,breif them on requirement and procedure of assignment. aim is to stress assignment subject ,active relative cultural background ,lighten recognition process burden on pupil. Pattern available is: first,teacher should assist pupil to understand assignment subject and target,all class put heads together by use of pictures,personal experience so as to stick out new words and phrases useful; in the next place ,teacher should offor preparatory time for pupil to think how to accompish assignment,so that pupil think it over what they want to speak and how to speak ,improve expressive quality at assignment stage as well; thirdly, teacher should offer record similar to somthing for pupil in accompishing assignment ,if,which base on a piece of article,pupil may read section of it;etc.