1Cook, V. J. Language teaching methodology and the L2 user perspective[A]. In V. J. Cook (ed.). Portraits of the L2 user[C]. Clevedon: Multilingual Matters, 2002.
2Duff, P. & C. Polio. How much foreign language is there in the foreign language classroom[J]. Modern Language Journal, 1990(74): 154-166.
3Krashen, S. The Input Hypothesis: Issues and Implications[M]. Harlow: Longman, 1985.
4Macaro, E. Codeswitching in the L2 classroom: a communication and learning strategy[A]. In E. Llurda(Ed.). Non-native language teachers: Perceptions, challenges and contributions to the profession[C]. New York: Springer, 2005.
5Wardhaugh, R. An Introduction to Sociolinguistics(6th ech'tion)[M]. Oxford: Wiley-blackwell, 2010.
