3Nunan, D. Designing Tasks for the Communicative Clauroom[ M ] . Cambridge: Cambridge University Press, 1989.
4Skehan, P. A Framework for the Implementation of Task-based Instruc-don[J]. Applied Linguistics , 1996a 17:38 - 62.
5Skehan, P. A Cognitive Approach to Language Learning [ M ]. Oxford University Press, 1998.
6Willis, J. A Framework for Task-based Learning[M].London: Longman, 1996.
7Long, 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.
8Wells, G. Language Development in the Pre-school Years [ M ]. Cambridge: Cambridge University Press, 1985.
9Skehan, P. Inddvidual Differences in Second-language Learning [ M ].London: Edward Amold, 1989.
10Krashen, S and Seliger, H. The Essential Contributions of Formal Instruction in Adult Second Iamguage Learning. TESOL Quarterly, 1975 /9, 173 - 83.
