语法复习：定语从句
定语从句考点
1、关系代词that –which; whose; which –as 的法比较；
2、关系代词和关系副词的用法比较；
3、介词加关系代词引导的定语从句；
4、定语从句与并列句的区别。
（一）定语从句一般由关系代词和关系副词引导
1、关系代词：who, whom, whose, which, that, as
2、关系副词：when, where, why
Where的特殊用法：如果定语从句分别修饰point, situation, stage, condition和case等表示抽象意义的词，且从句句子结构完整时，常用where 引导，意思是“到了某种地步，在某种境况中”。
关系代词和关系副词必须位于从句之首，先行词之后，起着连接主句和从句的作用；关系代词替代先行词的作用；同时在从句中又充当句子成分。
3、关系代词和关系副词的用法：
1）当先行词为人时用who 作主语，whom作宾语；
2）当先行词为物或整个句子时用which ，可作主语或宾语或表语；
3）先行词为人、物时用that ，可作主语或宾语或表语；
4）whose用作定语，可指人或物；这时可以与of which 结构互换，词序是：“the+名词+of which或of which+ the+名词或whose+名词”。
5）关系副词when（指时间，在定语从句中作时间状语，where（指地点，在定语从句中作地点状语），why（指原因，在定语从句中作原因状语）。
（二）限制性定语从句与非限制性定语从句
1、限制性定语从句：从句与主句关系密切，去掉从句，主句意义不完整，甚至不合逻辑。
e.g. I was the only person in our office who was invited.（去掉定语从句，意思就不完整）
2、非限制性定语从句：从句对先行词关系不密切，去掉定从句，意思仍然完整。形式上用逗号隔开，不能用that和why来引导。
e.g. Tom’s father, who is over sixty, still works hard day and night.（who引导非限制性定语从句，整个句子可分成两句来翻译）
（三）使用定语从句时特别注意的几个问题
1、that与which的区别。
1）用that而不用which的情况：
①先行词为不定代词all, a lot, (a) little, few, much, none, anything, something, everything, nothing 等词时
②当先行词被all, any, no, much, little, few, every 等限定词所修饰时
③当先行词是序数词或形容词最高级时或被序数词或形容词最高级所修饰时。
④当先行词被the very, the only, the next, the last等所修饰时。
⑤当先行词为指人和指物的两个并列名词词组时。
⑥当主句是以which /who开头的特殊疑问句时。
⑦当有两个定语从句时，其中一个已用which另一个宜用that
⑧当先行词在主句中做表语而关系代词也在从句中做表语时
2）用which而不用that的情况：
①引导非限制性定语从句，关系词代表整个主句的意思；
②先行词本身是that时
③介词+ 关系代词。
3）as引导定语从句时的用法
①as引导限制性定语从句通常用于the same …as, such …as, so…as, as…as 结构中。
e.g. I want the same shirt as my friend’s. 我要一件跟我朋友一样的衬衫。
Such machines as are used in our workshop are made in China. 我们车间使用的这种机器是中国制造的。
②as引导非限制性定语从句既可放在主句之前，也可放在主句之后，用来修饰整个句子。通常用下列句型：as is known to all, as is said, as is reported, as is announced, as we all know, as I expect 等。
e.g. As I expected, he got the first place again in this mid-term examination. 正如我所预料的那样，他在这次期中考试中又获得了第一名。
3）as 引导非限制性定语从句时与which的区别
①as 引导的从句可以放在主句之前，而which 引导的从句只能放在主句之后。
②which引导的非限制性定语从句which没有词义，而as常译成“就象……那样、正如所……的”。
2. 关系代词在从句中作主语时，从句的谓语动词单数还是用复数应由先行词决定。
e.g. The man who lives downstairs speaks English fluently. 住在楼下的那个人英语说得很流利。
The students who are in Grade Three are going to climb the hill tomorrow.
3. 定语从句有时不直接紧靠先行词，中间由一个定语、状语或谓语隔开。
e.g. There is an expression in his eyes that I can’t understand.
4. 引导定语从句的关系副词有时可以用“介词+ which”来代替。
e.g. October 1, 1949 was the day on which ( = when ) the People’s Republic of China was founded.
5. 当定语从句中谓语动词是带介词或副词的固定短语动词时，短语动词的各个固定部分不要拆开。
e.g. The sick man whom she is looking after is her father.
6. 介词在关系代词前，只能用which和whom，且不能省略；介词在句尾，关系代词可有which, that, whom。
e.g. The man (whom/ who/ that) you were talking about has come to school. 7．定语从句与同位语从句的区别。
①定语从句引导词被称为关系词，that充当主语、宾语、表语。有时可省略。
②同位语从句引导词被叫做连词，that不能充当任何成分，不可省。
Word came that their army was defeated.(同位语)
We expressed to them our wish that was the same as their.(定语)
8．定语从句与强调句型的区别
It was in the hotel that we stayed last night.（强调句）
It was the hotel where/in which we stayed last night. (定语从句)
9. the way 在从句中作状语，其中的关系词有三种不同的表达方式。1) the way + that; 2) the way 后省略关系词; 3) the way + in which。
10．几个特殊的定语从句句型：
①He is the only one of the students who has got very good marks
in the match.（句中one为先行词）
He is one of the students who have got good marks in the match.（句中students 为先行词）
②Is this place the one (that) we visited yesterday?
Is this the place(that / which)we visited yesterday ?
③He stood at the window, from where he could see what was happening.
④It may rain, in which case the match will be put off.
二、定语从句用法其他要点：
1. 非限制性定语从句与并列句的区别：
关键是看两个句子之间是否有连词，若有表示并列关系的连词或分号，那就是并列句；如果两句之间没有这些连接符号，那就是非限制性定语从句，此时就需考虑使用适当的关系代词或关系副词了。
2. 注意the same …as /that和such…as/that的区别
This is the same instrument that I used yesterday. 这就是我昨天用过的那台仪器。
This is the same instrument as I used yesterday. 这台仪器跟我昨天用过的那台一样。
(the same …as /that均为定语从句，that表同一个人或物；而as表同类但不是同一个)
This book is written in such easy English as beginners can understand.（定语从句）This book is written in such easy English that beginners can understand it.（结果状语从句）
（such…as为定语从句as在句中做主语、宾语或表语而such…that为结果状语从句that在句中不做任何成分）
3.one of +名词复数+关系代词+复数动词
the only one of +名词复数+关系代词+单数动词
He is one of the boys who like playing basketball.
He is the only one of the boys who likes playing basketball.
4.当关系代词as/which引导非限制性定语从句，as/which在从句中做主语且先行词为整个主句时，从句谓语动词要用单数。
He passed the driving test, which surprises all of us.
5. 当先行词时time，若time做“次数”讲时，应用关系代词that引导定语从句，that可省略；若time做“一段时间”讲时，应用关系代词when引导从句。
This is the first time that the president has visited the country.
There was a time when there were no radios, no telephones or no TV sets.
6. 介词+which/whom+不定式结构
The poor man has no house in which to live.=The poor man has no house to live in.
=The poor man has no house in which he can live.