8Farhady, H. Measures of language proficiency from the learner's perspective [J]. TESOL Quarterly, 1982, 16(1).
9Larsen-Freeman, D. and M. H. Long. An Introduction to Second Language Acquisition Research [M ].London and New York: Longman.1991.
10Ma, Guanghui. The Relationships of L2 Learners'Linguistic Variables to L2 Writing Ability [D].Unpublished Doctoral Dissertation. The Nanjing University, 1998.