Lesson 121 The man in a hat
定语从句：
关系代词
whom
先行词是人，whom + 及物动词/不及物动词 + 介词
当介词提前的时候，关系代词不能省略。
The man is my uncle.
I spoke to the man.
The man whom I spoke to is my uncle.
The man to whom I spoke is my uncle.
当介词提前的时候，先行词是物时，只能用which
I have a sister.
She lives in Paris.
I have a sister who lives in Paris.
The man who has white hair is Mr.White.
I have a friend whose father is a teacher.
whom
I see you everyday.
I look at the blackboard everyday.
The man who we met is my uncle.
speak to sb.
I spoke to the man.
The man whom I spoke to is my uncle.
The man to whom I spoke is my uncle.
which 是指人以外的生命或没有生命的东西。
先行词（物） + which + 动词
He likes the house.
The house has a lot of windows.
He likes the house which has a lot of/many windows.
The books are on the desk.
The books are mine.
The books are on the counter.
The books which are on the counter are mine.
The dog is his.
The dog is carrying a basket.
The dog which is carrying a basket is his.
The dog carrying a basket is his.
Those men are making all that noise.
Those men are repairing the road.
Those men who are repairing the road are making all that noise.
Those men repairing the road are making all that noise.