2Breen, M. P. Learner Contributions to Task Design [A].In Language Learning Tasks [C]. Ed. Candlin and Murphy. Englewood Cliffs, NJ:Prentice Hall International, 1987.
3Donate, Richard. Collective Scaffolding in Second Language Learning [ A]. In Vygotsky Approach to Second Language Research [ C]. Ed. Lantolf, J. et al. New York: Adlex Publisher, 1994.
4Fisher, E. Distinctive Features of Pupil-Pupil Classroom Talk and Their Relationship to Learning: How Discursive Exploration Might be Encouraged [ A ]. In Language, Literacy and Learning in Educational Practice [C]. Ed. Stierer, B. London: The Open University Press, 1994.
5Foster, F. & Skehan, P. The Influence of Planning on Performance in Task-Based Learning [ J ]. Studies in Second Language Acquisition,1996.
6Kumaravadivelu, B. Language-Learning Tasks: Teacher Intention and Learner Interpretation [ J ]. ELT Journal , 1991.
7Mercer, N. Neo-Vygotskian Theory and Classroom Education [ A]. In Language, Literacy and Learning in Educational Practice [ C ]. Ed.Stierer, B. London: The Open University Press, 1994.
8Wood, D., Bruner, J. S., & Ross, G. The Role of Tutoring in Problem Solving [J]. Journal of Child Psychology and Psychiatry, 1976.
