but 做为关系代词,用在 no,one,或 none 之后,后接一个从句,but 在从句中作代词用,代替某物或某人,其含意是否定的;从句相当于 that 或 who引导的否定意义的从句。这样,整个句子就是双重否定,语气强于一般肯定句。有强烈的感染力。例如:1.No one is in the world but knows the Great Wall. but as a relational pronoun is used after no, one, or none, followed by a clause, but in the clause as a pronoun, instead of something or someone, its meaning is negative; clause is equivalent to that or who guided Negative clause. In this way, the entire sentence is double negative, tone stronger than the general affirmative sentence. Has a strong appeal. For example: 1.No one is in the world but knows the Great Wall.