2[1]Schumann,J.affective variables and the problems of Age in Second language acquisition[J].Language learning,1975,(25):209-35.
3[2]Selinker,L.language transfer and fossilization:the multiple effects pri nciple[C].In Suan M.Gass and Larry Selinder language transfer in language le arning.Newbury House,Rowley,Massachusetts,1992.
4[3]Selinker,Zhao Hong Han.Fossilizaiton:what we think we know[M].intern et,1996.
