3[1]Swain, M. Communicative competence: Some roles of comprehensible input and comprehensible output in its development [A].Grass,S. & Madden(eds. ). Newbury House, 1985.
4[2]Brown,H. D. Teaching by Principles :An Interactive Approach to Language Pedagogy[M]. Prentice Hall Regents,1994.
5[3]Poulisse, N. The Use of Cornpensatory Strategies by Dutch Learners of English[M]. Enschede: Sneldruk,1990.