4Hyland, K. Hedging in academic writing and EAP textbooks [ J ].English for Specific Purposes, 1994, 13(3): 239- 255.
5Hyland, K. Writing without conviction? Hedging in science research articles [J]. Applied Linguistics, 1996,17(4): 433 - 454.
6Kuo, Chin-hua, The use of personal pronouns: Role Relationship in scientific jonrnal articles [J]. English for Specific Purposes, 1999, 18(2):121 - 138.
7Myers, G. The pragmatics of politeness in scientific articles [J]. Applied Linguistics, 1989, 10(1): 1-35.
8Rounds, P.L. Multifunctional personal pronoun use in an educational setting [J]. English for Specific Purposes, 1987, 6(1): 13-29.
