一.关系副词where(=介词+which) 在从句中作地点状语

　　T have never been to the town where(in which) I was born.我从未去过我出生的那个城镇。

　　Everyone wants to visit the pace where(in which) Premier Zhou once worked.

　　大家都想参观周总理曾工作的地方。

　　二.关系副词when(=介词+which) 在从句中作时间状语

　　I will never forget the day when(on which) I joined the League.我永远忘不了我人团的那一天。

　　He came at a time when(at which) we needed help.他在我们需要帮忙的时候来了。

　　3.关系副词why(=for which) 在从句中作原因状语，通常与reason连用

　　We don't know the reason why(for which) they didn't finish their homework on time.

　　我们不知道他们为什么没有按时完成作业。

　　There is no good reason why(for which) she should leave so soon.

　　她没有充分的理由要这么快离开。