所谓相关词，主要是指在主从复合句的主句中跟从句或不定式相呼应的代词、副词或代副词，因此，也称呼应词。相关词形式多样，用法不一，在有些句型中是必不可少的，在有些句型中又是可有可无的，它有时没有词义，有时不仅有词义而且又能起到强调句子语气的作用。现把其用法归 The so-called related words, mainly refers to the main clause from the compound sentence with the subordinate or infinitive echoes adverbs, adverbs or vice adverbs, therefore, also known as echo. Various forms of related words, different usage, in some sentence patterns is essential, in some sentence is optional, it sometimes does not have meaning, and sometimes not only the meaning of the word but also play a strong emphasis on the tone of the sentence Role. Now its usage returns