[1] Swain, M. Communicative competence: Some roles of comprehensible input andcomprehensible output in its development[A]. In S.M. Gass and C.G. Madden (eds.) Inputin Second Language Acquisition[C]. Rowley, MA: Newbury House, 1985: 235-256.[2] Swain, M. Three functions of output in second language learning[A]. In G. Cook andB. Seidlhofer (eds.) For H. G. Widdowson: Principles and Practice in the Study of Language. AFestschrift on the Occasion of his 60th Birthday[C].Oxford: Oxford UniversityPress, 1995: 125-144.[3] Swain, M. & Yang, L. Output Hypothesis: Its history and its future. 外语教学与研究,2008(1):45-51.[4] Vygotsky,L.S. Mind in society: The Development of Higher PsychologicalProcesses[M].Cambridge, MA: Harvard University Press,1978