在定语从句中巧用“还原法”
定语从句是英语基础语法的一部分，同时也是高中阶段语法教学中的重要部分。但许多高一学生在定语从句的掌握和运用方面存在困难，做题时感觉云里雾里，采用“还原法”能帮助理清思路。
一、何为“还原法”
“还原法”是指将因语法需要而改变的句子恢复其原来的模式，以检验所做的答案正确与否。
二、“还原法”的运用
1.将先行词还原到定语从句中，确定其在句中所充当的成份，以选择正确的关系词
例1 He has moved to the house____he was born.
A.which B.that C.when D.where
例2 He has moved to the house____is newly painted.
A.which B./ C.when D.where
这两个句子粗看似乎一样，但若分别把先行词house还原到定语从句中：第一句为“He was born in the house.“,house与介词一起做地点状语，应选择D；第二句定语从句还原为“The house is newly painted.“，先行词在句中作主语，关系代词不可省略，所以选择A。
再看下面两题：
例3 This is the reason____he asked us to carry out the plan.
A.because B.why C.which D.when
例4 This is the reason____he gave us for carrying out the plan.
A.because B.why C.which D.when
例3、例4的先行词都是the reason，但通过还原，我们知道前一句中the reason担当了定语从句的原因状语，即he asked us to carry out the plan for the reason，故应选B；后一句中the reason充当定语从句的宾语，即he gave us the reason for carrying out the plan,C为正确选项。
2.还原主句，理清主从句之间的关系，以免误入“陷阱”
例5 Alac asked the policeman____he worked to contact him whenever there was an accident.
A.with him B.who C.with whom D.whom
如果把he worked to contact him理解为定语从句，那就很难明白先行词the policeman与定语从句的关系。因此，我们应先还原主句：Alac asked the policeman to contact him whenever there was an accident，此时我们就能明白先行词the policeman与定语从句的关系是“he worked with the policeman”，所以根据句意应该选择C。
例6 I’ll do everything____you.
A.I can to help B.I can help C.what I can to help D.that I can help
在选择时，学生很容易想到情态动词can后接动词原形，会选B或D。但用还原法来检测一下，就会发现主句应为：I’ll do everything to help you，其中every thing是定语从句I can(do)的先行词，关系代词that省略，所以A才是正确答案。
3.把问句还原成陈述句，有助于正确理解句子
例7 Is this museum____we visited last year
A.where B.the one C./ D.at which
例8 Is this the museum____we visited last year
A.where B.the one C./ D.at which
把例7还原成陈述句This museum is____we visited last year，我们就可清楚地看到从句前缺少先行词和关系代词，因而应该选B(the one=the one that)。但如果把例8还原成陈述句This is the museum____we visited last year，我们会发现本句有先行词，只是缺少相应的关系代词，因此应选择C（句中省略了that或which）。
总之，利用还原法做题，可以帮助我们理解语法知识，提高答题的准确率。定语从句
定语从句一般都跟在它所修饰的名词后面，所以如果在名词或代词后面出现一个从句，根据它与前面名词或代词的逻辑关系来判断是否是定语从句。
1. 三个需要掌握的概念:
1. 定语从句:在复合句中,修饰主句中某一名词或代词的从句.
2. 先行词:主句中被定语从句所修饰的名词或代词.
3. 关系词:引导从句并代替先行词在定语从句中充当相应成分的词.
关系词
The girl who is under the tree is Mary.
先行词 定语从句
关系词按其在定语从句中充当成分的不同可以分为关系代词和关系副词.
2. 关系代词 [who,whom,which,that,whose,as]
1. 关系代词根据先行词及其在从句中所充当成分的不同,用法上存在差异.具体见下表:
成分先行词 主语 宾语 定语
人 Who/whom/that Who/whom/that/-- whose
物 Which/that Which/that/-- whose
作宾语时可省略.
He has a friend whose father is a doctor.(指人,作定语)
The chair whose leg was broken has been repaired. (指物，作定语)
The girl who is singing is Mary.(指人,作主语,不可省略)
The girl (who/whom/that) I met is Mary.(指人,作宾语动词met的宾语,可省)
The girl (who/whom/that) we talked about is Mary.(指人,作介词about的宾语,可省)
[试一试]
(1). The man _________ is shaking hands with my father is a policeman. (who/that)
(2). The professor _________________ you wish to see has gone to Shanghai. (who/whom/that/--)
(3). I live in a room _________ windows face the south. (whose)
(4). The old woman was very happy to get back the gold ring _______________ she had lost on the plane. (/which/that/--)
2. (5). China is a country ____________ has a long history. (that/which)
3. 介词+which/whom引导的定语从句
The girl (who/whom/that) we talked about is Mary.
= The girl about whom we talked is Mary.
English is the subject (which/that) Tom is interested in.
= English is the subject in which Tom is interested.
观察可知:当先行词在从句中充当介词宾语时,介词可以通常提到关系代词之前.
(1) 当先行词为人时,用”介词+whom” ==>此时关系代词不可用who/that,也不可省.
(2) 当先行词为物时,用”介词+which” ==>此时关系代词不可用that,也不可省.
(3) 介词的选用:
1. Do you know the man____________ you just shook hands (从句谓语动词搭配) (with whom)
2. I’ll never forget the day____________ I joined the Party.(先行词搭配) (on which)
3. Water is very important for us____________ we can’t live.(句子含义) (without which)
采用”还原法”,将先行词放回从句中,再来判断,选用合适的介词.
[试一试]
①.In the dark street there was nobody ____________ I could turn for help. (to whom)
②Yesterday we had a meeting ____________ we discussed many problems. (at which)
③.The dog, __________ she used to be afraid, is her favourite animal now. (of which)
④.Water, ______________ man can’t live, is really important. (without which)
⑤.This is the man ______________ I learned the news. (from whom)
⑥. This is the man, _______________________ is a famous writer.(他的儿子…) (whose son)
⑦. The old man has two sons, __________ are doctors.(他们都是医生) (both of whom)
⑧. There are a lot of dictionaries here, ______________ is mine.(没有一本是我的) (none of which)
⑨. I bought some books from the bookstore, _________ were English novels.(其中5本) (five of which)
⑩. She has six children, __________________ is John.(最聪明的) (the smartest of whom)
. I lived in London for six months, ___________I learned some English. (在此期间) (during which)
4. that和which的用法：
A. 先行词指物时只用that,不用which的情况:
(1)当先行词为all,everything,nothing,anything,little,much,等不定代词时；
Tell me everything that you know.
He told us all that he had done.
(2)当先行词被very, both, the only, all, every, no, any, little, much, some等修饰时；
And then I watched all the glasses that were on the table fall off onto the floor.
This is the only English-Chinese dictionary that I have.
(3)当先行词被序数词修饰时；
This is the last lesson that we have this term.
(4)当先行词被形容词最高级修饰时：
This is the most beautiful city that I have visited.
(5)当先行词既包括人又包括物时；
(6)当主句是以who或which开头的特殊疑问句时；
Which is the coat that you like best
Who is the man that was talking to you
(7)当先行词在定语从句中作表语时，无论先行词是人还是物；
China is no longer the country that she was.
(1) 先行词指物时不用that,而用which的情况:
(2) 先行词在从句中作介词宾语且介词提至关系代词之前时,用”介词+which”；
(3) 非限定性定语从句中.
[试一试]
①.I have said all ______ I want to say. (that/--)
②.There is little work ______ you can do. (that/--)
③.This is the first play ______ I have seen since I came here. (that/--)
④.This is the very book _____ I want to buy. (that/--)
⑤.They talked about the men and the things ______ they saw. (that/--)
⑥.Which is the hotel ______ he once stayed at (that/--)
⑦.Who is the woman _____ shook hands with you just now. (that/--)
⑧.China isn’t the country ____ it was. (that)
⑨.This is the car in _______ we went to Shanghai. (which)
⑩.He is often late for school, ______ makes the teacher very angry. (which)
5. as引导的定语从句：
(1) as用于引导限定性定语从句中,先行词既可指人也可指物,既可作主语,也可以作宾语,常和such,so以及the same连用.此时不用其它关系代词.
I’ve never heard such stories as he told.(先行词为物,as在从句中作宾语)
He is such a student as everyone likes. .(先行词为人,as在从句中作宾语)
This is the same tool as I used last time.(这和我上次用的工具是同一类的)
[对比: This is the same tool that I used last time.(这和我上次用过的工具是同一个)]
(2) as用于引导非限定性定语从句,可代表整个主句,引导的定语从句可以放在主句之前或主句之后,用逗号与主句隔开.
As is know to all, Taiwan is part of China.
He is from the south, as we can know from his accent.
[试一试]
1. She wears the same hat ____________ I wore yesterday.(as)
2. This is such an interesting story _________ everybody likes to read. (as)
比较This is such an interesting story __________ everybody likes to read it.(that)
3. ______ everyone knows, China is a developing country. (As)
4. ______ is known to us all, the moon travels round the earth once every month. (As)
5. The number of the students in high schools is increasing,_____ is mentioned above. (as)
比较He says his father is famous, ______ is a lie.[定语从句的内容对主句的内容起消极作用,了解] (which)
3. 关系副词 [where, when, why]
1. where. 先行词为表示地点的名词,在从句中充当地点状语,相当于”介词+which”
The house where/in which Luxun once lived has become a place of interest.
2. when. 先行词为表示时间的名词,在从句中充当时间状语,相当于”介词+which”
I still remember the day when/on which I first came to this school.
3. why. 先行词为reason,在从句中充当原因状语,相当于”for which”
The reason why/for which Tom was late for class was that he missed the early bus.
[试一试]
(1)I will never forget the day _____________ I joined the Party.(when)
(2)What is the name of the town _____________ we stayed yesterday evening. (where)
(3)This is the school ________________ I used to teach English in the 1980s. (where)
(4)I don’t know the reason ______________ he left Japan. (why)
(5)I will never forget the days _______________ we spent together. (which/that/--)
(6)This is the school ______ I visited 10 years ago. (which/that/--)
(7)Is that the reason _______ you gave me (which/that/--)
采用”还原法”,将先行词放回从句中,判断出先行词在从句中作何种成分,再选择合适的关系代词或关系副词.
4. 限定性从句与非限定性定语从句
1. 限定性定语从句:与先行词关系密切,对先行词起限定作用.
2. 非限定性定语从句:与先行词关系并不十分密切,对先行词起补充说明作用.
[试比较]
(1). In the class there are ten students who speak English well.
(2). In the class there are ten students, who speak English well.
如何判断 (看从句前有无逗号)
(3). Mary, ____________ you saw yesterday, is my younger sister.(who/whom)
注意:非限定性定语从句中关系词不用that,在从句中作宾语时也不可省略.
