定语从句中的介词问题
形容词从句中的介词如何处理，大致可分三种情况。

1.属于: of which/whom = whose
The family lived in an old house.
The roof of the house had fallen in.
先行名词以“of +原词”、或“原词’s” 形式带入从句。

分别对应关系词为of which和whose+名词。

I had many false friends at that time.
One of them betrayed me. （背叛）
先行名词以“of + 原词（人）” 形式带入从句。

对应关系词of whom。

【注】who和whom唯一区别是——前有介词、后接whom。

2.时空: 介+which =where/when
Lin’an is a small city.
I was born in that city.
先行名词以“in + 原词（地点）” 形式带入从句。

对应关系词in which或where。

（我们也可以理解为：先行名词还是原词带入，只是因为介词提前了，所以用which）
【注】that不能代替which的两种情况：1、介词后；2、非限定从句、先行词为前面整个事件（句子）。

3.依此类推：基本原则是用关系词代替先行词，不要打扰介词！
The person should be here soon.
I'm doing the project with him.
先行名词以原词形式带入从句、with提前，只能用whom。

I’d like to thank my father.
I would not have succeeded without his support.
先行名词以“原词’s” 形式带入从句, 前面原本就有个介词without。

His first job is in a big bank.
He learnt a lot of information about financial management from the job.
先行名词以原词形式带入从句。

前面原本就有个介词from。

【技巧小结】
1.无论题目如何复杂，基本原则不变，即：关系词代替先行名词！
2.先行名词在原句中的作用：原词、属格（of型或“‘s“型）、介词宾语。

3.注意that和which、who和whom的适用条件区分。