6Genesee, F &Upshur, John A. Classroom-based Evaluation in Second Language Education [ M ]. Beijing: Foreign Language Teaching and Research Press,2001.
7Holec, H. Autonomy and Foreign Language Learning [ M ].Oxford: Pergamon, 1981.
8Vygotsky L S. Mind in Society: The Development of Higher Psychological Processes [ M ]. Cambridge, Mass : Harvard University Press, 1978.
9Wertsch J V. Voices of the Mind : A Sociocultural Approach to Mediated Action[M]. Oxford: Harvard University Press,1991.
