4Prabhu,N.S.Second Language Pedagogy[M].Oxford:Oxford University Press,1987:24.
5Williams,M.& Burden,R.L.Psychology for Language Teachers[M].Beijing:Foreign Language Teaching and Research Press,2000:21,42.
6Long,M.H.A role for instruction in second language acquisition[A].In K.Hyltenstam and M.Pienemann (Eds.).Modelling and Assessing Second Language Acquisition[C].Clevedon Avon:Multilingual Matters,1985:89.
7Breen,M.P.Learner Contributions to Task Design[M].London:Prentice-Hall International,1987:23.
8Nunan,D.Designing Tasks for the Communicative Classroom[M].Cambridge:CUP,1989:1,10,47-48.Communicative Tasks and the Language Curriculum[J].TESOL Quarterly,25:2.
9Willis,J.A Flexible Framework for Task-based Learning[A].In Willis,J.& Willis,D.Challenge and Change in Language Teaching[C].UK:Macmlillan Publishers Limited,1996:52-62.
10Richards,J.C.et al.Longman Dictionary of Language Teaching and Applied Linguistics (Third Edition)[M].Beijing:Foreign Language Teaching and Research Press,2005:693.