1. 在 all, nobody, no one, somebody, someone, anybody 等詞之后兩者都可用，但以用 that 較普通。如：

All that [who] heard him were delighted. 所有聽了他講話的人都很高興。

Have you met anybody that [who] has been to Paris? 你遇見過到過巴黎的人嗎?

2. 在序數(shù)詞、形容詞最高級以及 the only, the same, the very 等之后兩者都可用，但以用 that 較普通。如：

Newton was one of the greatest men that [who] ever lived. 牛頓是世界上最偉大的人物之一。

He is the only one among us that [who] knows Russian. 他是我們中間唯一懂俄語的人。

3. 引導(dǎo)非限制性定語從句時，通常只用 who。如：

Mrs Smith, who has a lot of teaching experience, will be joining us next term. 史密斯夫人很有教學(xué)經(jīng)驗(yàn)，她下個學(xué)期將來與我們一道工作。

4. 但是在下列情況，通常只用 that：

①當(dāng)先行詞是一個既指人又指物的并列詞組時。如：

I made a speech on the men and things that I had seen abroad. 我就我在國外所見到的人和事作了報告。

②當(dāng)先行詞是 who 時(為避免重復(fù))。如：

Who that has sympathy can laugh on that occasion? 有同情心的人誰會在那個時候發(fā)笑呢?

③當(dāng)關(guān)系代詞在定語從句中作表語時(可省略)。如:

Tom is not the boy (that) he was. 湯姆這孩子已不是以前那個湯姆了。