1Cook. V Usiag the first langue in the classroom[J]. The Canadian modem Language Review,2001(3).
2Skiba, R. Code Switching as a Countenance of Language Interference [J].The Intemet TESL Journal,2005. (http://iteslj. org/Articles/Skiba - Codeswitching. html).
3Verschueren, J. Understanding Pragrnatics[ M ]. London and New York: Amonld 1999.
4Browan, P. And Levinson, S. Politeness: Somt Universals in Language Usage[ M ]. Cambridge: Cambridge University Press. 1987: 62.
