定语从句中，何时用关系代词，何时用关系副词？

1.关系代词在后面跟着的定语从句中做主语、宾语、表语、定语等，有：who,whom,whose,that,which,as等。
2.常见的关系副词有：where,when,why等。这些关系副词在后面的定语从句中作状语，表示时间、地点、方式、原因等。
3.判断何时用关系代词，何时用关系副词，关键是要分析定语从句中缺少的是什么成分，是主宾语还是状语之类的。

关系代词:
主 格 who which that
宾 格 whom that that
所有格 whose of which/whose of which/whose

关系副词=介词+关系代词
例如：where=in which,when=on which,why=for which

例句：
1 the year when he was born (when = in which)
=the year in which he was born
2 the day when they arrived (when = on which)

3 the hotel where they were staying (where = in/at which)

4 the reason why he refused is ....