介词+which|whenhe 和介词+whose 的区别,再加上例句

（1）which
主要引导定语从句,定语是做修饰成分的,功能是限定成分.例如:
The pen which is green is mine.
这里which 引导的is green是对钢笔颜色的修饰,所以用which..
which可指人,亦可指物,做宾语时可省略.
（2）whose
指某人的或某物的,在定语从句中做定语,不可省略.
指物时,常用the+n.+of+which 的结构来代替.
The classroom whose door is broken will soon be repaired.
=The classroom the door of which is broken will soon be repaired.
门破了的那个教室很快将被修好.
（3）where
和以上词语最大的不同在于它是关系副词,而其他的为关系代词.where指地点,代替先行词在定语从句中做地点状语.
Shanghai is the city where I was born.