一、关系副词引导的限制性定语从句
关系副词在引导定语从句时，其功能相当于介词短语，在从句中作状语。引导定语从句的关系副词有when、where、why。
[观察例句]
1．That's the cinema where we often go and see films.
2．He enjoyed the four years when he studied in Suzhou.
3．Do you know the reason why the sky is blue?
[归纳用法]
1．when指时间，在定语从句中作时间状语。
I still remember the day when I first went to the Great Wall.
我还记得我第一次去长城的那一天。
2．where指地点，在定语从句中作地点状语。
The house where I lived ten years ago has been pulled down.
我10年前居住的那所房子已经被拆了。
3．why指原因，在定语从句中作原因状语。
The reason why he succeeded in the exam is that he studied very hard.
他考试成功的原因是他学习很认真。
