1Harmer J..The Practice of English Language Teaching[M].London:LONGMAN,1991:153.
2Skmen,J.Anita..Current Trends in Teaching Second Language Vocabulary.In Norbert Schmitt&Michael Mc Carthy(Ed).Vocabulary:Description,Acquisition and Pedagogy[C].Shanghai:Shanghai Foreign Language Education Press,2002:237—257.
3Firth,J.R..Paper in Linguistics[M].London:Oxford University Press,1957.