定语从句that who whom的区别和例句总结如下：

定语从句that who whom都可指代人，但用法有所区别。

一、限制性定语从句中：

A．在从句中作主语时，可用who或that，who较为常用

The woman who/that won the contest also won last year. 

赢得比赛的那位女士也赢得了去年的比赛。

The manager who/that employed me was called Steven. 

聘用我的经理叫史蒂芬。

B．在从句中作宾语时，可用who、that或whom，或将关系词省略；

whom最正式，口语中常省略关系词或用that或who

I can describe the person that/who/whom I saw. 

我可以描述我见到的那个人。

=I can describe the person I saw.

在从句中作宾语时，若介词提前，只能用whom，此时whom不可省略

The boy to whom you spoke is my friend. 

和你讲话的男生是我的朋友。

（whom不可省）

C．先行词是those时，关系词常用who

God helps those who help themselves. 

上帝帮助那些能够自己帮助自己的人。

Success belongs to those who are willing to work hard. 

成功属于那些愿意努力工作的人。

D．先行词有the very/the only/the same等修饰时，常用that

You are the only student that wants to be a singer. 

你是唯一一个想要成为歌手的学生。

This is the same man that I saw the other day. 

这就是我前几天见到的同一个人。

E．关系词在从句中作表语时，用that，或将that省略

Mary is no longer the girl that she was. 

玛丽已经不是以前那个玛丽了。

=Mary is no longer the girl she was.

Washington's early life shaped him into the great man that he later became.

华盛顿早期的生活将他塑造成他后期所成为的伟人。

=Washington's early life shaped him into the great man he later became.

F．若先行词包含有人和物时，常用that

She talked about the earth and men that Aristotle once talked about. 

她谈论了亚里斯多德曾经谈论过的地球和人类。

G．主句以疑问词who开头时，常用that，以避免重复

Who is the girl that is standing there? 

站在那里的女孩子是谁？

Who is the woman that has black hair? 

有黑色头发的那位女士是谁？

H．若先行词带有形容词最高级或序数词时，常用that

She was the most beautiful girl that I ever saw. 

她是我见过的最漂亮的女孩。

It was the best decision that I ever made. 

这是我做过的最好的决定。 

You are the first girl that I know. 

你是我知道的第一个女孩子。

I．强调句中，较常用that： It is….that….

It was John that you saw. 你看到的是约翰。

It was Steve Jobs that/who created the new product. 

设计出新产品的是史蒂夫乔布斯。(在从句中作主语时，也可用who)

二、非限制性定语从句中：

A．在从句中作主语时，用who ， that不用于非限制性定语从句中

Einstein, who was born in Germany, is famous for his theory of relativity. 

爱因斯坦生于德国，他因相对论而闻名。

Steven, who stole the wallet, is at large.

史蒂芬偷了钱包，他在潜逃。

B．在从句中作宾语时，用who或whom，whom较正式，who较常用；介词前置时用 whom

She was introduced to the author, who/whom she was excited to meet. 

她被介绍给了那个作者，她很激动见他。

This woman, with whom he had lived for two years, had never known him. 

这女人和他住在一起两年了，她从来都没有了解他。

以上就是定语从句中关系词that who whom的区别，希望对你有所帮助。你可能还需要查看：定语从句that which的区别