介词的选用可根据从句中的相关词组确定，该介词通常可以放在关系代词之前，也可放在从句之尾。下面是小编辛苦为大家带来的定语从句修饰句子【4篇】，希望能够给予您一些参考与帮助。
做定语从句的时间状语。
I still remember the day when I first came to Beijing.
I still remember the day on which I first came to Beijing.
（ 介词＋which可以代替 when）
I’ll never forget the time when we worked on the farm.
[I remember the days which//that we spent together.]
修饰表示人的先行词。 例如:
This is the man who helped me.
Do you know the comrade who spoke just now ？
The boy who//whom we saw yesterday is John’s brother.
as用作关系代词和关系副词引导限定性定语从句，在从句中作主语、定语、表语、或状语，常与the same … as; such… as ， so… as ， as… as 连用。
I like the same book as you do.
I want to have such a dictionary as he has.
I shall do it in the same way as you did.
He is the same age as you （ are ）。
He will give you such information as will help you.
Such students as you have mentioned should be criticized.
=Students such as you have mentioned should be criticized.
在the same…后也可用that引导定语从句，但意义有所不同：
that 引出的定语从句，指的是与先行词同一事物；而 as引出的定语从句是与先行词相似的'同类事物。
I want to use the same tool that I used yesterday.
I want to use the same tool as I used yesterday.
口语中可以省略。
The doctor (whom) you are looking for is in the room.
The person (whom) you just talked to is Mr. Li.
=The person to whom you just talked is Mr. Li. （介词后 whom不能省略）
The babies whom the nurses are looking for are very healthy.
（固定短语中的介词一般不省略，介词仍放在动词之后）