关系副词(when,where,why)引导的定语从句
when的先行词一般是表示时间的名词，when在定语从句中作时间状语。
I'm looking forward to a day when we can enjoy a clean and quiet environment.(划线部分为定语从句，作定语修饰前面的先行词“a day”，关系副词“when”在定语从句中作时间状语。)
我盼望有一天我们能够享有清洁宁静的环境。
I will never forget the day when I watched on TV the Chinese astronautswaving their hands in the outer space.
我永远也忘不了在电视上看到中国的宇航员在外太空招手的那一天。
where的先行词一般是表示地点的名词，where在定语从句中作地点状语
The museum is the place where people can get educated and entertained.(划线部分为定语从句，作定语修饰前面的先行词“the place”，关系副词“where”在定语从句中作地点状语。)
博物馆是人们受教育并可以娱乐的地方。
The zoo is an ideal research centre where scientists can conduct someexperiments on animals to discover the causes of some diseases and developsome new cures.
动物园是个理想的研究中心，在这里科学家们可以做动物实验从而找出一些疾病的成因并研发出新的疗法。
why的先行词是表示原因的名词(只有reason), why在定语从句中作原因状语
The reason why many young students go to study abroad is that they can savour aforeign culture and master a foreign language.(画线部分为定语从句，作定语修饰前面的先行词“the reason”，关系副词“why”在定语从句中作原因状语。)
很多年轻学生出国留学的原因是他们可以体味国外的文化并且能精通一门外语。
This is the reason why I am not in favour of the installation of cameras inpublic areas.
这就是为什么我不赞成在公共场所安装摄像头的原因。
学生常犯错误如下:
Do you know the reason why she did it for? (误)。
Do you know the reason why she did it? (正)。
Do you know the reason which she did it for? (正)。
