3[1]Leech,G.N.Principles of Pragmatics[M].London:Longman.1983.
4[2]Yule,George.Pragmatics[M].Shang Hai:Shang Hai Foreign Language Education Press.2000.
5Allwright, D. 1984. The importance of interaction in classroom language learning [J]. Applied Linguistics 5: 156-171.
6Blum-Kulka, S. 1989. Playing it safe the role of conventionality in indirectness [A]. In S. Blum-Kulka et al (eds.) . Cross-cultural Pragmatics: Requests and Apologies [C]. Alex Publishing Corporation.
7Blum-Kulka, S. 1990. You don't touch lettuce with your fingers: Parental politeness in family discourse [J]. Journal of Pragmatics 14: 259-288.
8Brown, P. & S. Levinson. 1978. Universals in language use: politeness phenomena [A]. In E. N. Boody (ed). Questions and Politeness: Strategies in Interaction [C]. Cambridge: CUP.
9Brown, P. & S. Levinson. 1987. Politeness: Some universals in language usage [A]. Studies in International Sociolinguistics 4 [C]. Cambridge:CUP.
10Ervin-Tripp, S., J. Guo & M. Lampert. 1990. Politeness and persuasion in children's control acts [J].Journal of Pragmatics 14/2: 307-331.