5Be/lack, A. A. , H. M Kliebard, R.J. Hyrnan & F. L. Smith. The Language of the Classroom[M]. New York: Teachers College Press, 1966 : 32 - 33,.
6Ellis, R. Understanding Second Language Acquisition [M]. Oxford: Oxford University Press. 1985: 75 - 77.
7Wiseman, D. G &G H. Hunt. Best Practice in Motivation and Managernent in the Classroom [M]. Springfield, Illinois: Charles Thomas Publisher Ltd. , 2001:60 - 61.
8Krashen, S. The Input Hypothesis: Issues and Implications [M]. London: Longman, 1985: 87- 91.
9Long, M. Linguistic and conversational adjustments to non-native speakers [J]. Studies in Second Language Acquisition, 1983, (5): 177 - 193.
10Swain, M. Communicative competence: Some roles of comprehensible input and comprehensible output in its development [A]. In S, Gass and C. Madden (eds.). Input in Second Language Acquisition [C]. Rowley, Mass. : Newbury House, 1985:103 - 104.
