1Rod Ellis. 1997. Second Language Acquisition [M] .Shanghai: Shanghai Foreign Language Education Press, 2000.
2Krashen, S. 1981. Second Language Acquisition and Second Language Learning [M] . Oxford: Pergamon.
3Krashen, S. 1985. The Input Hypothesis: Issues and Implication [M] . London: Longman.
4Schumann J. The acquisition of English negation by speakers of Spanish: A review of the literature[C]//In R. Andersen (ed.) The Acquisition and Use of Spanish and English as First and Second Languages. Washington DC: TESOL, 1979: 1-32.
5Krashen S. The Input Hypothesis: Issues and Implications[M]. London: Longman, 1985: 2.
6Wode H. Language acquisition universals: A unified view of language acquisition[C]//In H. Winits (eds.). Native Language and Foreign Language Acquisition. 218-234. Annals of the New York Academy of Sciences. 1981, 379.
7Larsen-Freeman D & M. Long. An Introduction to Second Language Acquisition Research[M]. London: Longman,1991: 142.
8Ellis R. The Study of Second Language Acquisition [M]. (2ed.) Oxford: Oxford University Press, 1994: 26. 509.
9Schwartz B. On explicit and negative data effecting and affecting competence and linguistic behavior[J]. Studies in Second Language Acquisition, 1993, (55): 147-163.
10Krashen S. The input hypothesis and its rivals[C]//In Ellis, N (eds.). Implicit and Explicit Learning of Languages.London: Academic Press, 1994: 45-77.
