2Chaudron, C. Second Language Classroom: Research on teaching and learning [ M ]. Cambridge: Cambridge University Press, 1988.21 - 27.
3Walsh, S. Construction or obstruction : teacher talk and learner involvement in the EFL classroom Language Teaching Research [ M ]. Language: Teaching Research, 2002.3 - 23.
4Nunan, D. Communicative Language Teaching: Making it Work [ M]. ELT:Journal, 1987. 136 - 145.