三个关系代词“who/that/which/ , 完全可以指代“单数名词/复数名词”或者“单数代词/复数代词”引导定语从句，这是不用质疑的。这种语言现象十分常见在英语课文，英语小说，英语文章，英语杂志以及所有的英语语法书中都随处可见，不需要权威语词典，正规词典或语法著作提供。网友可以放心使用。

【1】单数名词+who/which/that+从句

The man who is sitting next to Tom comes from the UK.

This is the house that Tom bought two years ago.

The car which Mike’s father bought five years ago is still new.

【2】复数名词+who/which/that+从句

The boys who came to Tom’s birthday party last night are his best friends.

The pens which were bought by his father last year write so smoothly.

Those trees that were planted five years ago are growing well

【3】单数代词+who/which/that+从句

He who laughs last laughs best.

He who makes no mistakes makes nothing.

What’s that which is under the desk?

【4】复数代词+who/which/that+从句

Those that are interested in the job should apply for it.

Those who break the law will be punished.

Those who want to visit the science museum may sign their names on the paper.

Those +that引导定语从句 是不用质疑的。

英语完全可以说 those that——这里的 that 不仅可以指物（包括动物）也可以指人。指人时 those that 相当于 those who，指物时 those that 相当于 those which。如：

Those that adapted best survived. 适应性最强的就活下来了。

Many of those that live in the north are tall. 许多住在北方的人个子都高。

None are so deaf as those that will not hear. 最聋的人莫过于不愿听别人意见的人。

Extinct volcanoes are those that have not erupted in historic times. 死火山指有史以来没有喷发过的火山。

网友要词典依据，我查了一下，Quirk的“语法大全”有一节（第12.19节）是专门讲这个问题的：