高考英语语法复习系列之1---定语从句Part one----基础知识I. 定语可以由形容词、代词、数词、名词、分词、不定式、介词短语等来担任，修饰名词。
(以分词、介词短语为例）例：The girl behind the tree is Kate.The man driving too fast was a drunk在英语中，修饰名词或代词的句子叫定语从句。
例：The girl who is behind the tree is Kate.The man who was driving too fast was a drunk定语从句起了形容词的作用，在句中修饰一个名词或代词。
被修饰的词叫做先行词，引导定语从句的词叫关系词，他的作用一是放在先行词与定语从句中间起了连接作用，二是在从句中担当一个成分，并与先行词保持数的一致。
普通代词与关系代词的区别I have a sister. She works in Shanghai. she代替sisterI have a sister who/that works in Shanghai.❑普通代词：只起代替的作用（如上例she)❑关系代词：（如上例who/that）1. 除了代替先行词外，2.它还在定语从句中担任一定的成分，3. 同时连接先行词与它引导的定语从句。
（把主句和从句连起来）关系词的选用与判断正确选择关系词是掌握定语从句的关键。
关系词的选择完全取决于先行词在定语从句中IV．介词+关系代词：1）介词后面的关系词不能省略。
2）that前不能有介词。
3）某些在从句中充当时间，地点或原因状语的"介词+关系词"结构可以同关系副词when 和where 互换。
This is the house in which I lived two years ago.This is the house where I lived two years ago.Do you remember the day on which you joined our club?Do you remember the day when you joined our club?4）介词的位置变化以及相应的关系词的变化。
请分析下面两个句子。
①那就是他工作的大学。
┏ at which he works.┣ which he works at.That is the college ┣ where he works.┣ that he works at.┗ he works at.②它出生的那一天是1952年8月20日。
┏ on which he was born┣ which he was born onThe day ┣ when he was born was Aug.20,1952.┣ that he was born on┗ he was born on总结：介词的选择是根据先行词与介词的搭配关系而定。
1.as与which都可以引导一个非限制性定语从句，并代表前面整个句子或主句中的表语。
He married the girl，as(which)was natural.He seemed a freigner,as(which)in fact he was.不同的是：as引导的定语从句可以前置，而which不行。
As was natural, he married the girl.2. 在the same…as,such…as,as…as结构中，same,such,as之后应是名词或形容词＋名词。
We are facing the same problems as we did years ago.Some people have no doubt that their cat understands as many words as a dog does.We hope to get such a tool as he is using.这三种结构也可以用which改写。
但要去掉这种结构，不能直接用which代替as。
以上三句分别可以改写成：We are facing the problems which we faced years ago.Some people have no doubt that their cat understands the words which a dog understands.We hope to get the tool which he is using.3.the same…as与the same…that引导的定语从句在意义上的区别是：前者修饰的是与原物同样的；而后者修饰的就是先行词同样的东西。
是比较：This is the same watch as I lost.这和我丢失的那一只表一样。
（不是同一只）This is the same watch that I lost这就是我丢失的那一只表。
（同一只）VII. 定语从句与其它从句1.定语从句与同位语从句的区别。
首先看引导从句的关系词that是否在从句中充当句子成分。
如果在从句中充当主、宾、表，则是定语从句。
再看that前的名词是否是一些需要有内容的名词，如：idea, fact, thought, news等。
后面的从句是说明其内容的，（这个名词在后面的从句中部充当任何成分），这个从句则是同位语从句。
He expressed the hope that he has had for many years.hope在从句中不充当句子成分，又加上后面从句是说明hope的内容的，因此时同位语从句。
We heard the news that pleased everyone.We heard the news that our term had won.2. 定语从句还是状语从句1）Here is such a big stone as no one can move.2) Here is so big a stone as no one can move.3) Here is such a big stone that no one can move it4) Here is so big a stone that no one can move it.在1) 2)句中as 都在定语从句中做了move 的宾语，as是引导词，引导定语从句，而在3) 4)句中，that 上作来引导状语从句的。
3. 定语从句还是地点状语从句1）I’ll go to the place where you stay.2）I’ll go where you stay.在句1）中where是引导定语从句，而在句2）中where是引导在点状语从句的。
4．定语从句还是主语从句1）As is known to all, they are sure to win.2）It’s known to all that they are sure to win.在句1）中as是关系代词，代表后面的整个句子做主句的主语。
在句2）中it是代词，代表that引导的句子做主句的主语。
5. 独立句与定语从句分不清1）I met twenty students, some of whom are good at maths.2）I met twenty students. Some of them are good at maths.3）We reached the mountain, on the of which we saw a beautiful scene4）We reached the mountain. On the of it (or: On its top ) we saw a beautiful scene 1）和3）是主句和定语从句关系，所以我们要用关系代词，而在2）4）各两句中，它们是各自的独立句子，所以用代词。
当然在36中将on the top of which改为on whose top,则定语从句的关系更为明显。
6. 定语从句与what引导的名词性从句的转换1）He’s not the man that he was.2）He’s not what he was.3）China is no longer the country that it was.4）China is no longer what it was.我们常用名词+that改变成what的形式，如1）2）句，它们的意义基本上是一样的，只不过用名词+that更为清晰。
3）4）句也是如此。
7. 区别清"It +be"引导的强调句与带有定语从句的复合句。
请看下列两组句子:A. It was September 11, 2001 ________ the World Trade Center in New York was attacked.B. It was on September 11, 2001_______ the World Trade Center in New York was attacked.A. It was Wuhan ____________ Jill met the three-year-old girl and adopted her.B. It was in Wuhan ____________ Jill met the three-year-old girl and adopted her.以上两组A、B句除了分别相差介词on 和in之外,其余部分完全相同。
但一词之差句式不同,横线上的词也不同。
那么究竟哪个是强调句,哪个是含定语从句的复合句呢?有一个简单的判定方法:去掉It was和连接词(横线部分)。
如果剩余部分仍是一个完整的句子,则是强调句;否则,那个空格中所用的引导词及其引导的部分就是定语从句。
根据这个原则我们就很容易判断出两组的A句是含定语从句的复合句,横线部分分别用关系副词when 和where。
而B句则是强调句,横线部分应是that。
Part two 方法点拨定语从句的辨认（思考步骤）1. 找出先行词a.确定在从句中关系代词的人称、数和性。
b.确定定语从句的位置2. 确定关系代词在从句中的成分以确定关系代词的格3. 确定从句的时态（定语从句的时态都不受主句的限制）The woman who/that spoke at the meeting yesterday is my mother.(主句)The woman is my mother.(叙述客观事实用一般现在时)(从句)The woman(who/that) spoke at the meeting yesterday.(句中yesterday表示过去时间)判断关系代词与关系副词方法一：用关系代词，还是关系副词完全取决于从句中的谓语动词。