定语从句的引导词怎么使用

如题

定语从句：
关系词有关系代词和关系副词。关系代词有that, which, who, whom, whose, as等；关系副词有where, when, why等。
关系词常有3个作用：1，引导定语从句。2，代替先行词。3，在定语从句中担当一个成分。
(一）关系代词引导的定语从句
1.who指人，在从句中做主语
The boys who are playing football are from Class One.
2. whom指人，在定语从句中充当宾语，常可省略。
Mr. Liu is the person (whom) you talked about on the bus.
3. which指物，在定语从句中做主语或者宾语，做宾语时可省略
Football is a game which is liked by most boys.
This is the pen (which) he bought yesterday.
4. that指人时，相当于who或者whom；指物时，相当于which。在宾语从句中做主语或者宾语，做宾语时可省略。
The number of the people that/who come to visit the city each year rises one million.
5. whose通常指人，也可指物，在定语从句中做定语
He has a friend whose father is a doctor.

宾语从句通常由that 引导，做一个动词或者介词的宾语，如，He said that he was a good student. that 引导的部分做了say 的宾语
定语从句很重要的就是在从句中作成分。引导词有that，which，who, whom, in which, by which, why ,when, where等。 where 是表示地点的引导词，如 He was in the school where he used to play basketball. where 通常可以换成介词加上which 的形式，如在例子中，where就可以用in which来代替

I once lived in a house whose roof has fallen in.
（二）介词+关系代词引导的定语从句
关系代词在定语从句中做介词宾语时，从句常由介词+关系代词引导
The school (that/which) he once studied in is very famous.
The school in which he once studied is very famous.
（三）关系副词引导的定语从句
1. when指时间，在定语从句中做时间状语
I still remember the day when I first came to the school.
2. where指地点，在定语从句中做地点状语
Shanghai is the city where I was born.
3. why指原因，在定语从句中做原因状语
Please tell me the reason why you missed the plane.
city in which./where I was born.
（四）限制性定语从句和非限制性定语从句
1.限制性定语从句： 不用逗号和主句隔开；是先行词不可缺少的定语，不能删除；翻译成先行词的定语，“…的…”；在关系词的使用上，做宾语时可省略、可用that 、可用who代替whom。
2.非限制性定语从句：用逗号和主句隔开；是对先行词的补充说明，删除后意思仍完整；通常翻译成主句的并列句；在关系词的使用上，不可省、不用that 、不用who代替whom。
限制性定语从句举例：
The teacher told me that Tom was the only person that I could depend on.
非限制性定语从句举例：
His mother, who loves him very much, is strict with him.