中学英语定语从句知
识点归纳
That is one of the most interesting books that are sold in the bookshop. 那是这家书店出售的最有趣的书之一。

The first thing that we should do is to get some food. 我们该做的第一件事是弄点吃的。

* 3）当先行词有：the only , the very , the same , the last 等修饰时。

例如：
My necklace is not the only thing that's missing. 我的项链不仅是丢掉的东西。

* 4）当主句以who或which开头时，定语从句中引导词用that ,不用which 或 who ，以避免重复。

例如：
Who is the girl that is wearing a red coat? 正穿一件红色外套的女孩子是谁？
* 5）当先行词既有人又有物时，用that 。

例如：
The writer and his novel that you have just talked about are really well known .你刚才谈起的那位作家以及他的小说确实很著名。

2、只用which不用that的情况：
* 1) 关系代词前有介词时； e.g. This is the room in which Lu Xun lived.
* 2)非限定性定语从句中；作宾语用的关系代词也不能省略。

e.g. That necklace, which you gave me as a present, was lost yesterday.
He has a daughter, who works in a hospital.
* 3) 先行词本身是that时； e.g. The clock is that which tells the time
非限定性定语从句的作用是对所修饰的成分作进一步说明，通常是引导词和先行词之间用逗号隔开，将从句拿掉后其他部分仍可成立。

Charles Smith, who was my former teacher, retired last year. 查理史密斯去年退休了，他曾经是我的老师。

（非限)
There is somebody here who wants to speak to you这里有人要和你说话(限制性)
* 4) which还有一种特殊用法，它可以引导从句修饰前面的整个主句，代替主句所表示的整体概念或部分概念。

在这种从句中，which可以作主语，也可以作宾语或表语，多数情况下意思是与and this 相似，并可以指人。

He did very well in the competition, which made his parents very happy.
* 关系代词whom，which 在定语从句中作介词宾语时，可以和介词一起放于先行词与定语从句之间，有时为了关系紧凑也可以将 whom 与 which 与先行词紧挨着书写，而将介词置于定语从句的后面，
That was the room in which we had lived for ten years.
= That was the room which we had lived in for ten years.
* 像listen to, look at, take care of等固定短语动词，在定语从句中一般不宜将介词与动词分开。

例如：This is the boy whom she has taken care of.。