3[1]Dickinson,L.Self-instruction in language Learning[M].Cambridge:Cambridge University Press,1987.
4[2]Holec,H.Autonomy and Foreign Language Learning[M].Oxford:Pergamon Press,1981.
5[3]Warschauer M.,& Kern,R.Network-based Language Teaching:Concepts and Practice[M].Cambridge:Cambridge University Press,2000.
6[4]Welsh,T.M.Distance education and the World Wide Web[J].In B.H.Khan (ed.).Web-based Instruction[C].Englewood Cliffs,NJ:Educational Technology Publications,1997:75-80.
