1Krashen SD. The Input Hypothesis: Issues and Applications.[M]London: Longman, 1985.
2Weissberg, R. Promoting acquisition in the conversation class[J]. English Teaching Forum,1988,(24)4.
3Seliger H. Psycholinguistic Issues in Second : Anguage Acqui-sition. Studies on Language Acquisition (unpublished test-book) [M]ed.Gujia-zu 1998.
4Swaine M. communicative competence: Some roles of com-prehensible input and comprehensible output in its develop-ment. Input in Second Language Acquisition[C]. ed. S. Gass and C.Madden.Rowley,Mass:Newbury House, 1985.
