定语从句中的关系代词有that, which, who, whom, whose等。其中，who whom 可指人，which可指物，whose，that可代替人或物。我们都知道关系代词在句中主要是代替先行词是人或物的名词或代词，表达该先行词的意思，有着主语，宾语，定语的作用。
1.在从句中作主语

A.The young man who came in just now is a lecturer.
刚才进来的年轻男士是个学者。

B. Here comes the good news. The team who won the basketball game is from Class two.
好消息传来了。赢得篮球比赛的这支队来自二班。

C.Visitors that come from different places are deeply attracted by the scenery there.
来自不同地方的参观者深深地被这儿的景象所吸引。

2.在从句中作定语
A.Fortunately，I eventually live in a house whose(of which) rent is lower.
幸运的是，我最终住在了一个费用较低的房子里。

B. The old man whose son is an excellent artist is kind.
这个热心老人的儿子是个杰出的艺术家。

3.在从句中作宾语，其中关系代词前有介词时,指人用whom
A.She is the star with whom you have talked is the one I admire.
你所谈论的她就是这个我所崇拜的明星。（不可用that）

B.This is the watch which he found at the shop yesterday.
这是他昨天在商店找到的表。

C.Can you tell me where is the man that I saw from the picture?
你能告诉我从图片上看到的这个人在哪吗？

4.在从句中作表语,此时主要是that作为关系代词修饰先行词
A.This is a best age that we wish it to be.
这是我们希望的最好的时代。（that在be 作表语）