4Arnold, J.Affect in Language Learning [M]. Cambridge : Cambridge University Press, 1999.
5Duffy, G.& Roberts.Ambiguity Tolerance and Field Independence as Predictors of Proficiency in English as a Second Language [J].Language Learning, 1986 ( 36 ) : 27-35.
6Ehrman, M.E.Understanding Second Language Learning Difficulties[M].Thousand Oaks: Sage Publications, 1996.
7Ellis, R.The Study of Second Language Acquisition[M]. Beijing: Foreign Language Teaching and Research Press, 2000.
8Frenkel-Brnnswik, E.Intolerance of Ambiguity as an Emotional and Perceptual Personality Variable [J].Journal of Personality, 1994 ( 18 ) : 108-143.
9Horwitz, E.K., Horwitz, M.B.&Cope J.Foreign Language Classroom Anxiety[J], The Modern Language Journal, 1986 ( 70 ) : 125-132.
10MacIntyre, P.D.& Gardner, R.C.Language Anxiety: Its Relation to Other Anxieties and to Processing in Native and Second Languages[J].Langnage Learning, 1991 (41) 41: 513-534.