[观察例句]
1．Our guide，who was a French Canadian，was an excellent cook.
2．Peter，whom you met in London，is now back in Paris.
3．The boy，whose hat is red，studies very hard.
4．He will come here yesterday，when he will be free.
5．They went back to London，where was their hometown.
[归纳用法]
1．who引导的非限制性定语从句
My gardener，who is very pessimistic，says that there will be no apples this year.
我家的园丁非常悲观，他说今年将不结苹果。
2．whom引导的非限制性定语从句
Mr.Smith，from whom I have learned a lot，is a famous scientist.
史密斯先生是一位著名的科学家，我从他那儿学了许多东西。
3．whose引导的非限制性定语从句
whose是关系代词who的所有格形式，在从句中作定语。whose通常指人，也可指动物或无生命的事物。
The boy，whose father is an engineer，studies very hard.
那个小男孩学习很努力，他的父亲是位工程师。
The house，whose windows face north，belongs to him.
窗子朝北的那个房子是他的。
