【正确答案】Systemic-Functional linguistics aims to provide a taxonomy for sentences, a means of descriptively classifying particular sentences. Although it may not seem as influential as Chomsky's transformational-generative theory in some parts of the world, it is much more relevant to the needs of various groups of people who deal with language.
Halliday believes that language is what it is because it has to serve certain functions. In other words, social demand on language has helped to shape its structure.
Systemic-Functional linguistics is based on two facts: (1)language users are actually making choices in a system of systems and trying to realize different semantic functions in social interaction; and (2)language is inseparable from social activities of man. Thus, it takes actual uses of language as the object of study, in opposition to Chomsky's approach that takes the ideal speaker's linguistic competence as the object of study.

【答案解析】[解析] 此题考查的是韩礼德系统功能语言学的特殊之处。系统功能语言学的目标是为句子提供一套分类法，为特殊的句子描述性分类提供方法。韩礼德认为语言之所以成为语言，在于语言必须完成一定的功能。换言之，语言的社会需求帮助语言形成了自身的结构。