【正确答案】Metalingual function is one of the functions language has. Our language can be used to talk about itself. For example, we can use the word book to talk about a book, and we can also use the expression "the word book" to talk about the sign "book" itself. This is the metalingual function of language and meshes with the thematic function of language in functional grammar. Metalingual function makes the language infinitely self-reflexive: We human beings can talk about talk and think about thinking.

【答案解析】[解析] 此题考查的是考生对元语言功能的理解。语言可以用来讨论语言本身。比如说，我们可以用“书”指代一本书，也可以用“书这个词”来指代“书”这个词本身。这就是语言的元语言功能，与功能语法中语言的主位功能相契合。同时，考生还应该理解并掌握语言的其他六个功能：informative(信息功能)、interpersonal(人际功能)、performative(施为功能)、emotive(感情功能)、phatic communion(寒暄功能)、recreational(娱乐功能)。