定语从句：只能用that引导的十三种情况1.在there + be 的句型中，句子的主语是先行词，而且又是物。

例如：There are two novels that I want to read.我要读的有两本小说。

There is no work that can be done now. 没有什么工作现在能做的了。

2.当先行词为主句的表语或者关系代词为从句的表语时。

例如：This is the book that was bought yesterday.这就是昨天买的书。

Our school is no longer the school that it used to be. 我们的学校不再是以前的学校了。

3.以Here is (are)开头的句子时。

例如：Here is a film that will move anyone.这是一部将使任何人受感动的电影。

Here are two books that I will buy.这是我要买的两本书。

4.It is (high)time +定语从句中。

例如：It is time that we should have a rest.我们应该休息了。

It is high time that they started out. 他们该动身了。

5.当先行词是way等词时，关系代词用that或者in which在定语从句中作方式状语时，在口语中，常可省略。

例如：This is the way that my father did this work.这就是我父亲做此工作的方式。

She admired the way in which I answered the questions.她羡慕我回答问题的方式。

6.在双重限定性定语从句中，如果一个从句用who或者which引导时，那么另一个从句用that 引导。

例如：He is the student that I have ever see who can jump highest.他是我曾经看到过跳得最高的学生。

My brother studies in the school which is the most beautiful in our city that isn't far from here. 我的弟弟在我们的城市最美丽的学校读书，并且离这儿不远。

7.当先行词被the last , the very 和the only修饰时。

例如：This is the very pen that I am looking for. 这正是我找的钢笔。

The only book I want to read is missing. 我唯一想看的书不见了。

8.在强调句子中，并且以who ,which, what开头时。

例如：Who was it that was lost ?究竟是谁迷路了？（此句中，最好不用who来代替that，避免重复。

）What was it that you did last week?你上周究竟做什么了？9.当先行词有序数词时。

例如：You are the first person that I want to ask for.你是我要见的第一个人。

This is the second book that I have ever written.这是我写的第二本书。

10.当先行词被all, every, no , some, few , little, much, both等修饰时，例如：This is all that I want to say at the meeting.这就是我在会上要说的。

Have you any books that are worth reading?你有值的看的书吗？11.当先行词既指人又指物时。

例如：The professor and his achievement that I heard about are admired by them .我听说的那位教授和他的成就得到他们的赞美。

Let's talk about the persons and the things that we can remember.让我们谈论能够想起的人和事。

12.当先行词为anything、everything、nothing时，关系代词用that,不用which；但用something 时，用which或者that均可。

例如：Everything we have seen in China is moving.我们在中国看见的东西件件感人。

I have nothing that is worth reading.我没有什么值得一读的东西。

13.当先行词是疑问代词who时。

例如：Who that you have ever seen can beat him in chess?你曾见过谁能在棋艺上打败他？as 的用法：其通常和such\ the same连用，代指物在从句中做主语或宾语This is the same pen as I bought yesterday。

这种笔和我昨天买的笔一样（同样的但不是同一个）。

引导定语从句的关系词在从句中做宾语，因先行词被the same所修饰所以用as引导注意：上句与下句的区别This is the same pen that I used yesterday.这就是昨天我使用的那一支钢笔（指的是同一个）。

I studied in the same school as she did in Beijing.我和他在北京的同一所学校就读。

引导定语从句的关系词在从句中做宾语，因先行词被the same所修饰所以用as引导I want to have such a dictionary as he has.我想要一本和他的一样的字典。

引导定语从句的关系词在从句中做宾语，因先行词被such所修饰所以用as引导which的用法：关系代词，在从句中做主语或宾语，做宾语时通常可以省略（直接做介词的宾语时除外，不能省。

）The radio which he bought yesterday doesn't work now.他昨天买的收音机现在坏了。

引导定语从句的关系代词在从句中做宾语，代指物，故用which.Can you lend me the book which was written by Lun Xun..你能借我那本由鲁迅所写的书吗？引导定语从句的关系代词在从句中做主语，代指物，故用which.This is the park which is the most beautiful one in our city.这是我们这个城市最漂亮的公园。

引导定语从句的关系代词在从句中做主语，代指物，故用which.This is the map by which we can get to the forest.这是张地图，借助它我们能到达那个森林。

引导定语从句的关系代词在从句中做介词的宾语，代指物，故用which.第二、在非限制性定语从句中的区别：as的用法：①在从句中通常做主语代指整个主句，②表示的意思是正如正象③其引导的定语从句即可以放在主句之前也可以放在主句之后。

The Pacific is the largest ocean, as we all know.太平洋是最大的洋，这一点我们都知道（正如我们所知到的，太平洋是最大的洋）。

引导非限制性定语从句的as在从句中做know的宾语，其代指整个主句。

As we expect, we won the game.我们赢了，这一点在我们预料之中。

（正如我们预料的一样，我们赢了）。

引导非限制性定语从句的as在从句中做主语，其代指整个主句。

从句在主句的前面The earth is round, as we all know.地球是圆的，这一点我们都知道。

（正如我们所知到的一样地球是圆的）引导非限制性定语从句的as在从句中做know的宾语，其代指整个主句。

As is known to all, he is the best student in our class.众所周知，他是我们班上最好的学生。

（正如我们所知到的一样，他是我们班上最好的学生。

引导非限制性定语从句的as在从句中做主语，其代指整个主句。

which的用法：①关系代词，在从句中做主语或宾语，代指人或物。

②当代指整个主句时表示的意思是主句和从句之间是因果关系即因为所以。

③其引导的非限制性定语从句只能放在主句之后。

Tom suddenly fell ill, which made us sad.Tom突然病倒，这使得我们很伤心。

Which引导的非限制性定语从句在从句中做主语，其代指整个主句，主从句的关系是因果关系，因为他的病，所以我们伤心。

The road was too slippery, which caused lots of accidents.路太滑了，以至于引起了很多事故。

Which引导的非限制性定语从句在从句中做主语，其代指整个主句，主从句的关系是因果关系，因为路滑，所以出事。

He was angry, which made him cry.他太生气了以至于他哭了起来。

Which引导的非限制性定语从句在从句中做主语，其代指整个主句，主从句的关系是因果关系，因为生气，所以哭。

一、as引导的定语从句表示说话人对话语的看法、态度、依据、解释或评论。

具有下列特点：1．as用于引导定语从句时，具有“正如……、像……、由……而知”等语义。

如：He was strongly against the plan，as could be expected．（正如所料，他强烈反对这项计划。

）As he hoped he would，he saw the girl．（像他希望的那样，他见到了那个女孩。

）2．as引导的定语从句在语义上要和主句保持一致，而which可不一定，如果语义不一致，则要用which来替代as。

如：He married again，as（which）was natural．（他又结婚了，这是自然的。

）3．as引导的定语从句，其先行词可由以下词来修饰，the same ／such ／as等。

也可以由which来改写，但不可直接替换。

如：This is the same sum as was spent in that year on private motoring．＝This isthe sum which was spent in that year on private motoring．（这与那年用于私人汽车所花的费用相同。