回答:where 引导定语从句时,它是关系副词,作地点状语,相当于介词+which; which引导定语从句时,它是关系代词,指代事物、婴儿、动物名词或整个句子(限于非限制性定语从句),作主语或宾语。例如: The house where / in which he lived two years ago has been pulled down. 两年前他住过的房子已经拆掉了。 In the middle of the house stands a desk, where / on which there are many books. 在房子中间,放着一张桌子,桌子上面有许多书。 This is a desk where /at which Tom often sat writing novels before.这是一张汤姆以前写小说坐过的桌子。 He is a thief, which is known to us all. 他是一个小偷,这件事我们大家都知道。 The baby which is crying is my son. The wolf which we hunted yesterday was about twenty kilograms in weight.我们昨天捕捉的那只狼有二十公斤重。 The news which you heard is fake. 你听到的这个消息是假的。