定语从句例句简单的如下：
1、who指人在从句中做主语。
（1）The boys who are playing football are from Class One. 在踢足球的男孩们是一班的。
（2）Yesterday I helped an old man who lost his way. 昨天，我帮助了一个迷路的老人。
2、whom指人，在定语从句中充当宾语，常可省略。
（1）Mr. Liu is the person（whom）you talked with on the bus. 刘先生就是在公交车上和你聊天的那个人。
（2）Mr. Ling is just the boy whom I want to see. 凌先生恰巧就是我想见的那个男孩。
（3）The man who/whom you met just now is my friend. 你刚刚见到的那个人就是我的朋友。
注意：关系代词whom在口语和非正式语体中常用who代替，可省略。
3、which指物，在定语从句中做主语或者宾语，做宾语时可省略。
（1）Football is a game which is liked by most boys. 足球是大多数男孩都喜欢的游戏。
（2）This is the pen（which）he bought yesterday. 这是他昨天刚买的钢笔。
4、that指人时，相当于who或者whom；指物时，相当于which。
在定语从句中做主语或者宾语，做宾语时可省略。
（1）The number of the people that/who come to visit the city each year rises one million.
（2）Where is the man that/whom I saw this morning?
5、whose通常指人，也可指物，在定语从句中做定语。
(1) He has a friend whose father is a doctor.
(2) I once lived in a house whose roof has fallen in.