1， Structural view of language sees languages as a linguistic system made up of various subsystems (Larsen-Freeman&Long): Phonology, morphology, syntax.语言的结构观把语言看作是由各种子系统组成的语言系统（弗里曼&朗）：音位学、形态学、句法。2， Functional view: communicative needs of the learner (Johnson and Marrow), the functional view not only sees languages as a linguistic system but also a means for doing things. Most of our day-to-day language use involves functional activities: offering, suggesting, advising, and apologizing.功能观
