6Benson. Making sense of autonomous language learning: Conceptions of learning and readiness for autonomy[J]. Eng- lish Center Monograph, The University of Hong Kong. 1998 (3) :3-13.
7Laufer H. Why are more words, more difficult than other[J].All A Review,1990,15(1) :10-20.
8Verhallen M, Rob Schoonen. Lexieal knowledge in L1 and L2 of third and fifth graders [J ]. Applied Linguistics, 1998, 19 (4) : 425-470.
9Sinclair J. The Lexical item,in E. Weigand (ed) ,Contrastive Lexi- cal Semantics [M]. Amsterdam and Philadelphia:John, 1998: 1-24.
10Cook V. Second Language Learning & Language Teaching [M]. Britain:Edward Arnold, 1991.