A主格

用who或that，通常用who：

The man who robbed you has been arrested．

抢劫你的那个人已经被逮捕了。

The girls who serve in the shop are the owner’s daughters．

在店里接待顾客的那几个女孩都是店老板的女儿。

Only those who had booked in advance were allowed in．

只有那些预先订票的人可以进去。

Would anyone who saw the accident please get in touch with the police？

凡亲眼看见发生事故的人请与警方联系。

但是在all，everyone，everybody，no one，nobody和those后面，也可用that替代who：

Everyone who／that knew him liked him．

认得他的人都喜欢他。

Nobody who／that watched the match will ever forget it．

看了这场比赛的人都不会忘记它。

B动词的宾语

用whom，who或that。

指人的关系代词的宾格形式是whom，但这被认为是十分正规的说法。在口语中经常使用who和that来代替whom（that 比who更常用）；更加普遍的是索性把宾格关系代词省略：

The man whom I saw told me to come back today．

我见到的那个人叫我今天返回。或：

The man who I saw…

The man that I saw…

The man I saw…（省略关系代词）

The girls whom he employs are always complaining about their pay．

他雇用的那些女孩子们老是抱怨薪水太低。或：

The girls who he employs…

The girls that he employs…

The girls he employs…（省略关系代词）

C介词的宾语

用whom或that。

在正规的英语中介词通常位于关系代词之前，这时关系代词

必须使用whom这一形式：

the man to whom I spoke我跟说话的那个人

而在非正式的口语中经常把介词置于句末。这时用that来代替whom，但更加普遍的是索性省略关系代词：

the man who／whom I spoke to

the man that I spoke to

the man I spoke to

同样：

The man from whom I bought it told me to oil it．

卖给我这件东西的那个人嘱咐我给它上点油。或：

The man who／that I bought it from…

The man I bought it from…

The friend with whom I was travelling spoke French．

和我一起旅行的那个朋友讲法语。或：

The friend who／that I was travelling with…

The friend I was travelling with…

D所有格

关系代词的所有格只有whose这一种形式：

People whose rents have been raised can appeal．

那些被增加了租金的人可以上诉。

The film is about a spy whose wife betrays him．

这部电影是关于一个被自己妻子出卖的间谍的故事。