关系副词where主要用于修饰表示地点的名词，同时它在定语从句中用作地点状语。如：
This is the village where he was born.这就是他出生的村子。
与when的用法一样，注意不要一见到先行词为地点名词，就以为一定要用关系副词where来引导定语从句，同时还要看它在定语从句中充当什么成分——如果在定语从句中用作地点状语，就用where；如果在定语从句中不是用作时间状语，而是用作主语或宾语，那就不能用where，而要用that,which等。
which的用法
1、(用作疑问代词)哪一个,哪一些
Which is my seat?
哪个座位是我的.?
2、(用做关系代词)那一个,那一些
He also had a gun with which to defend himself.
他还有一把自卫用的枪。
He invited us to dinner, which was very kind of him.
他邀请我们吃晚饭,他这么做真是太客气了。
She was very fond of speaking French, which indeed she spoke well.
她很喜欢讲法语,而且确实讲得不错。
He lives in the house which is opposite ours.
他住在我们对面的那栋房子里。
which作为形容词用法如下
1、(用作疑问形容词)哪一个,哪一些
Which university did you go to, Oxford or Cambridge?
你上过哪所大学?牛津还是剑桥?
2、(用作关系形容词)这个,这些
The doctor told him to give up smoking, which advice he took.
医生叮嘱他戒烟,他接受了这一忠告。