3Hymes, D. On communicative competence In Pride and Holmes, 1972. Sociolinguistics [ C ]. Harmoundsworth, UK: Penguin : 198 - 200.
4Swain, M. , Communicative competence : Some rules of comprehensive input and comprehensive output in its development. In S. Gass & G. Madden (eds). Input in second language acquisition [ C ]. Rowley, MA : Newbury House. 235 - 253.
5Nattinger,J. R. , & DeCarrico, J. S. Lexical phrases and language teaching[M]. Oxford: Oxford University Press, 1992 :37 -44.
6Lewis, M. Implementing the lexical approach:Putting theory into practice [M]. Language Teaching Publications, 1997.