when，where，why作为定语从句的引导词，总称为关系副词。下面用句子合并的方法分析它们的使用。
一、where引导的定语从句
分析下面两个简单句：
句①I know a garden.
句②You can find wild strawberries there.
把句②变为句①的定语从句，句①中的agarden做定语从句的先行词。在句②中there指句①中提到的agarden也就是定语从句的先行词，there在句中做地点状语，因此要用where引导定语从句，代替句②中的there，也就是说there就不能出现在定语从句中了。
由此得到
③I know a garden where you can find wild strawberries.
句②还可以写作
④You can find wild strawberries in it.
it指句①中的garden，“在花园中”要使用介词短语in the garden。）
把句④变为句①的定语从句，因为it做介词in的宾语，先行词是agarden，指物。在这种定语从句中介词常常提到定语从句的开始，这时关系代词只能使用which替代it，it就不能在定语从句中出现了。
由此得到
⑤I know a garden in which you can find wild strawberries.
请把下面每组的两句话合并为一句，把第二句话变为第一句的定语从句。
第一组：
This is the village.
I was born there.
→This is the village where I was born.
第二组：
The lab is not far from here.
The chemist often does experiments there.
→The lab where the chemist often does experiments is not far from here.
二、when引导的定语从句
分析下面两个简单句：
句①We shall remember the days.
句②We studied together then.
把句②变为句①的定语从句，句①中的the days做定语从句的先行词。在句②中then指句①中提到的the days，也就是定语从句的先行词，then在句中做时间状语，因此要用when引导定语从句，代替句②中的then，也就是说then就不能出现在定语从句中了。
由此得到
③We shall remember the days when we studied together.
句②还可以写作句
④We studied together during the days
.介词短语during the days含义为“在这些日子里”)
把句④变为句①的定语从句，因为the days做介词during的宾语，先行词是the days，指物，在定语从句中介词during提前，用关系代词which替代the days，the days就不能在定语从句中出现了。
由此得到
⑤We shall remember the days during which we studies together.
请把下面每组的两句话合并为一句，把第二句话变为第一句的定语从句。
第一组：
I've always longed for the days.
I should be able to be independent then.
→I've always longed for the days when I should be able to be independent.
第二组：
There are moments.
I forget all about it then.
→There are moments when I forget all about it.
三、why引导的定语从句
分析下面两个简单句：
句①He wanted to know the reason.
句②I was late for the reason.
把句②变为句①的定语从句，句①中的the reasons做定语从句的先行词。因为the reason做介词for的宾语，先行词是the reason指物，在定语从句中介词for提前，用关系代词which替代the reason，the reason就不能在定语从句中出现了。
由此得到
③He wanted to know the reason for which I was late.
注意：在定语从句中当先行词为the reason(s)，定语从句由for which引导时，可以用why代替for which。
由此我们得到
⑤He wanted to know the reason why I was late.
请把下面两句话合并为一句，把第二句话变为第一句的定语从句。
The reason is not very convincing1.
He came for the reason.
→The reason why he came is not very convincing.
The reason for which he came is not very convincing.
