6Granger, S. Learner English on Computer[M ]. London: Longman, 1998.
7Biber, D. , Johansson, S. , Leech, G. , Conrad. S. & Edward, F. Longman Grammar of Spoken and Written English [M]. London: Pearson Education Limited, 1999. Beijing; Foreign Language Teaching and Research Press, 2000: 428.
4James C. Errors in Language Learning and Use:Explo- ring Error Analysis[ M]. Beijing: Foreign Language Teaching and Research Press,2001:1.
5Richards J C. Longman Dictionary of Language Teach- ing & Applied Linguistics[M]. Beijing: Foreign Lan- guage Teaching and Research Press, 2005:238,344.
6Corder S P. The Significance of Learners Errors[J]. In- ternational Review of Applied Linguistics, 1967 (4): 161 -169.
7Fuertes,R.F,Liceras,J.M. Copulao mission in the English developing grammar of English/Spanish bilingual children[J].Inter-national Journal of Bilingual Education and Bilingualism,2010,(05):525-551.
8Gass,S.M. Second Language Acqusition:An Introductory Course[M].{H}Routledge,London,2008.
