（1）which一般指代事物、动物,或者指代婴儿、小孩；who指代人或者拟人化的动物。which 表明先行词是物（也指事）在限定性定语从句中=that，在非限定性定语从句中只能which，不能用who。

The book which I bought is very cheap. 我买的'书非常便宜。 　　

I know the man who stole Mary's wallet. 我认识偷玛丽钱包的人。 　　

Which period of history would you most like to have lived in? 你最喜欢生活在哪一个历史时期？

（2）who 表明先行词是人（一般在从句中充当主语），which 表明先行词是物（也指事）在限定性定语从句中=that，在非限定性定语从句中只能which 。 　　

The boy who plays computer well is waitting for you. 那个电脑玩得很好的男孩正在等你。

This is the hotel which you will stay in. 这就是你将要住的旅馆。　

Tom is late for class, which makes his mum very angry. 汤姆上课迟到了，这使他妈妈很生气。

Beijing, which ia the capital of China, is a beautiful city. 北京是中国的首都，是一座美丽的城市。