In terms of category of words, it can function as notional word, such as verb, pronoun, conjunction, as well as functional word, such as auxilary word, emotional word, etc.

在词类上，它可以是实词，做动词、代词、连词等； 也可以是虚词，做助词、语气词等。

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But "is a very commonly used word. It can be used as a conjunction, a preposition, an adverb and a relative pronoun in sentences."

是一个十分常用的词，它既可以作连词、介词、副词及代词，又可以和其它词组合构成短语来表示许许多多的意思。

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