英语语法定语从句
基础知识学习
定语从句在复合句中作定语，修饰一个名词或代词，被修饰的名次或代词即现行词。定语从句通常出现在先行词之后，由关系词（关系代词或关系副词）引出。
关系代词有：which、that、who、whom 、whose 关系副词有：when 、where、why 定语从句的引导词既起引导从句的作用，同时又担任从句的主语、宾语、定语（whose）、和状语，在限制性定语从句中作宾语的关系代词可以省略，在非限制性定从中不可省。
考点一、由which、that引导的定从，在从句中作主语、宾语，指物
The building which/that stands near the river is our school.
I lost the book (which/that)you gave me.
考点二、由who、whom、that、whose在从句中主语、宾语、定语
This is the man who/that helped me.
I don’t know the man (who/whom/that)you talked with.
Nobody wants the house whose roof has fallen in.
the roof of which has fallen in.
of which the roof has fallen in.
考点三、使用关系副词应注意下列几点：
1. 关系副词在意义上都相当于一定的介词+ which结构：
when = on (in, at, during…) + which where = in (at, on…) + which why = for which
I was in Beijing on the day when (= on which) he arrived.
The office where (= in which) he works is on the third floor.
This is the chief reason why (= for which) we did it.
2. 当先行词是表时间和表地点的词时，一定要注意分析从句的结构，如果缺少主语或宾语时，关系词应该用which 或that; 缺少时间状语或地点状语时，才能用when 或where，I’ll never forget the day when my hometown was liberated.
I’ll neve r forget the days which / that we spent together last summer.
His father works in a factory where radio parts are made.
His father works in a factory which / that makes radio parts.
3. when 和where 既可以引导限制性定语从句，也可以引导非限制性定语从句。而why 只能引导限制性定语从句。
考点四、只用that 的情形
1. 先行词是不定代词all, (a)little, few, much,none, everything, something, anything, nothing,等
All that can be done has been done.
2. 先行词被all, any, no, much, little, few, every 等限定词所修饰时。
We heard clearly every word that he said
3. 先行词被形容词的最高级修饰时
This is the best film (that) I have ever seen.
4. 先行词被序数词修饰时
The first English novel (that) I read was A Tale of Two Cities.
5. 先行词被the only, the very 修饰时
The only thing that we can do is to give you some money.
6. 先行词既有人又有物时
Do you know the things and persons that they are talking about?
7. 当特殊疑问词由who或which 引导时，为避免重复，常用that代替who或which
Who is the man that is standing by the door?
Which is the dictionary (that) you bought yesterday?
8. 当先行词在主句中做表语，而关系代词也在从句中作表语
Shanghai is no longer the city that it used to be..
考点五、“介词+which/whom”引导的定语从句
1.当介词放在关系代词的前面时，介词宾语只用which 或whom ，关系代词不能省略
This is the house in which Shakespeare used to live.
In the dark street, there wasn’t single person to whom she could turn for help.
Recently I bought an ancient vase, the price of which was very reasonable.
2.复合介词短语+关系代词which”引导的定语从句，这种结构常与先行词用逗号分开，定
语从句常用倒装语序
He lived in a big house, in front of which stood a big tall tree.
3.介词+which/whom +不定式结构“
in which to live.
The poor man has no house in which he can live.
to live in.
考点六、关系代词as，which引导定语从句时的区别
1. As与which 都可以代指主句中的一部分或整个句子，有时可以互换，但是，当非限制性
定语从句放在主句前面时，只能用as,不能用which。
As is known to everybody, the moon travels round the earth once every month.
=It is known to everybody that the moon travels round the earth once every month.
=What is known to everybody is that the moon travels round the earth once every month.
2. 当as在从句中作主语时，后面常接动词的被动语态。如：be known, be said, be reported. be
announced等。如从句中行为动词是主动语态，一般用which作主语。
She has been absent again, as is expected.
Tom has made rapid progress, which makes me very happy.
3. as常用在As is often the case; as (it) seems likely, as {it} often happens, as (it) was pointed
out, as (it) was said earlier, as I remember (it),as I understand (it), as (it) appears等结构中。
Jack has won the first prize, as it often happen. (像往常一样)
As is pointed out, this is grammar problem.
考点七、定语从句中的谓语动词与先行词保持一致
