According to Skinner, language behavior can only be studied through observation of the（）factors.

填空题（）,is the study of how words combine to form sentences and the rules which govern the formation of sentences.

填空题According to the functionalists, language has three functions:（）,expressive, and social.

填空题The most common word order in English is（）,with other sentence constituents draped around these key parts in various ways.

填空题The（）approach to language is to see it in terms of the bits and pieces by means of which it is put together.

填空题The（）approach to language study is concerned with language as an instrument of social interaction rather than as a system that is viewed in isolation.