6Nunan, D. Designing Tasks for the Communicative Clauroom[ M ] . Cambridge: Cambridge University Press, 1989.
7Skehan, P. A Framework for the Implementation of Task-based Instruc-don[J]. Applied Linguistics , 1996a 17:38 - 62.
8Skehan, P. A Cognitive Approach to Language Learning [ M ]. Oxford University Press, 1998.
9Willis, J. A Framework for Task-based Learning[M].London: Longman, 1996.
10Long, M H. A Role for Instruction in Second Language Acquisition:Task-based Language Training[J]. In K Hyltenstam and M Pienemann( eds). Modelling and Assessing Second language Acquisition . London: Muhilingual Matters, 1985:77- 100.