3Aijmer,K.Modality in advanced Swedish learners‘ written interlanguage. Computer Learner Corpora, Second Language Acquisition and Foreign Language Teaching . 2002
4Gotti,M.Shall and Will in Contemporary English: A Comparison with Past Uses. Modality in Contemporary English . 2003
5Halliday MAK.An Introduction to Functional Grammar. . 2000
6Smith,N.Changesinthe modals and semi-modals of strong obligation and epistemic necessityinrecent British En-glish. Modalityin Contemporary English . 2003
7Xu,Hongliang.Xueshu Yupian zhong de Zuozhelichangbiaojiyu Yanjiu. (A Corpus-based Study of Authorial Stance Markers in Academic Research Discourse by Chinese Advanced EFL Writers). . 2007
8Biber D,Johansson S,Leech G,et al.Longman Grammar of Spoken and Written English. . 1999
9Martin JR.English Text: System and Structure. . 2004
10Sweetser,Eve.From Etymology to Pragmatics: Metaphorical and Cultural Aspects of Semantic Structure. . 1990