2Donato, R. 1994. Collective scaffolding in second lan- guage learning [A]. In J. p. Lantolf & G. Appel (Eds.), Vygotskian Approach to Second Language Research [C]. Norwood, N. J.: Ablex Publishing Corporation. 33-56.
3l%eire, P. & Macedo, P. 1987. Literacy." Reading the Word and World [M]. South Hadley, MA: Berin-Garvev.
4Krashen, S. D. 1985. The Input Hypothesis: Issues and Implications [M]. London: Longman.
5Larsen-Freeman, D. 2000. in Language Teaching niversity Press. Techniques and Principles [M]. Oxford: Oxford U- Swain, M. 1985.
6Communicative competence: Some roles of comprehensible input and comprehensible output in its development [A]. In S. Gass & C. Madden (Eds.), Input and Second Language Ac- quisition [C]. Rowley, MA: Newbury House. 235-256.
7Swain, M. & Lapkin, S. 1995. Problems in output and the cognitive processes they generate: A step to- wards second language learning [J]. Applied Lin- guistics, 16 (3): 371-391. Yu, G. 2004.
8Perception, practice and progress -- Sig- nificance of scaffolding and zone of proximal de- velopment for second or foreign language teachers [J]. Asian EFL Teaching Journal, 6 (4): 9-21.