8The New Media Consortium.The Horizon Report 2013 Higher Education Edition [EB/OL].(2013-04-28)[2013-10-03]. http: //www.net.edueause.edu/ir/librarylpdf/HR2013 .pdf.
9Moore.Three types of interaction[J].American Journal of Distance Education, 1989,(2): 1-6.
10Hiltz,S.R.'Evaluating the Virtual Classroom' in Harasim, L.(ed.) Online education: perspectives on a new environment. [M].New York: Praeger, 1990:133-184.