8Collentine, J. 2000. Insights into the construction of grammatical knowledge provided by user-behav- iour tracking technologies [J]. Language Learning & Technology 3: 44-57.
9Graziano, A. &M. Raulin. 1997. Research Methods: A Process of Inquiry EM]. New York: Longman.
10Hu, M. & P. Nation. 2000. Vocabulary density and reading comprehension -J]. Reading in a Foreign Language 13: 403-430.