管理员定语从句知识总结 总结就是对一个时期的学习、工作或其完成情况进行一次全面系统的回顾和分析的书面材料，写总结有利于我们学习和工作能力的提高，不如立即行动起来写一份总结吧。但是却发现不知道该写些什么，以下是小编精心整理的定语从句知识总结，希望对大家有所帮助。……
定语从句知识总结
总结就是对一个时期的学习、工作或其完成情况进行一次全面系统的回顾和分析的书面材料，写总结有利于我们学习和工作能力的提高，不如立即行动起来写一份总结吧。但是却发现不知道该写些什么，以下是小编精心整理的定语从句知识总结，希望对大家有所帮助。
定语从句的概念
在复合句中，修饰某一名词或代词的从句叫定语从句。被修饰的名词或代词叫先行词，定语从句一般放在先行词的后面。
定语从句的关系词
引导定语从句的关系词有关系代词和关系副词，常见的关系代词包括that， which， who(宾格whom，所有格whose)等，关系副词包括where， when， why等。关系代词和关系副词放在先行词及定语从句之间起连接作用，同时又作定语从句的重要成分。
定语从句的分类
根据定语从句与先行词的关系，定语从句可分为限制性定语从句及非限制性定语从句。限制性定语从句紧跟先行词，主句与从句不用逗号分开，从句不可省去，非限制性定语从句主句与从句之间有逗号分开，起补充说明作用，如省去，意思仍完整。
关系代词的用法
1. that 既可以用于指人，也可以用于指物。在从句中作主语或宾语，作主语时不可省略，作宾语可省略。例如：
Mary likes music that is quiet and gentle.玛丽喜欢轻柔的音乐。(that作主语)
The coat (that) I put on the desk is blue.我放在桌子上的那件外套是蓝色的。(that作宾语)
2.which用于指物，在句中作主语或宾语，作主语不可省略，作宾语可省略。例如：
The building which stands near the train station is a supermarket.位于火车站附近的那座大楼是一家超市。(作主语)
The film (which) we saw last night was wonderful. 我们昨天晚上看的那部电影很好看。(作宾语)
3.who， whom用于指人，who 用作主语，whom用作宾语。在口语中，有时可用who代替whom，也可省略。例如：
The girl who often helps me with my English is from England.经常在英语方面帮助我的那个女孩是英国人。(作主语)
Who is the teacher (whom) Li Ming is talking to?正在与李明谈话的老师是谁?(作宾语)
注意：
(1)当定语从句中含有介词，介词放在句末时，who， that， which可省略，但介词在关系代词前时，只能用“介词+which/whom”结构。例如：
This is the house in which we lived last year.这是我们去年居住的房子。
Please tell me from whom you borrowed the English novel.请告诉我你从谁那借的这本英文小说。
(2)含有介词的固定动词词组中，介词不可前置，只能放在原来的位置上。例如：
This is the person whom you are looking for. 这就是你要找的那个人。
(3)that 作介词的宾语时，介词不能放它的前面，只能放在从句中动词的后面。例如：
The city that she lives in is very far away.她居住的城市非常远。
(4)关系词只能用that的情况：
a. 先行词被序数词或形容词最高级所修饰，或本身是序数词、基数词、形容词最高级时，只能用that，而不用which.例如：
He was the first person that passed the exam. 他是第一个通过考试的人。
b.被修饰的先行词为all， any， much， many， everything， anything， none， the one等不定代词时，只能用that，而不用which.例如：
Is there anything that you want to buy in the shop?你在商店里有什么东西要买吗?
c.先行词被the only， the very， the same， the last， little， few 等词修饰时，只能用that，而不用which.例如：
This is the same bike that I lost.这就是我丢的那辆自行车。
d. 先行词里同时含有人或物时，只能用that， 而不用which.例如：
I can remember well the persons and some pictures that I saw in the room.我能清楚记得我在那个房间所见到的人和一些照片。
e.以who或which引导的特殊疑问句，为避免重复，只能用that.例如：
Who is the girl that is crying? 正在哭泣的那个女孩是谁?
f.主句是there be 结构，修饰主语的定语从句用that，而不用which.例如：
There is a book on the desk that belongs to Tom. 桌子上那本书是汤姆的。
(5)关系词只能用which，而不用that 的情况：
a.先行词为that， those时，用which， 而不用that.例如：
What’s that which is under the desk? 在桌子底下的那些东西是什么?
b.关系代词前有介词时，一般用which，而不用that.例如：
This is the room in which he lives. 这是他居住的房间。
c.引导非限制性定语从句，用which， 而不用that.例如：
Tom came back， which made us happy. 汤姆回来了，这使我们很高兴。
五、关系副词的用法
(1)when指时间，其先行词表示时间，在句中作时间状语。例如：
This was the time when he arrived.这是他到达的时间。
(2)where指地点，其先行词表示地点，在句中作地点状语。例如：
This is place where he works.这是他工作的地点。
(3)why 指原因，其先行词是原因，起原因状语作用。例如：
Nobody knows the reason why he is often late for school. 没人知道他为什么上学总迟到。
定语从句知识
定语从句由关系代词who、whom、whose、which、what、as和关系副词where、when、why等引导，但须记住：
1.what不能引导定语从句。
2.关系词的分析须考虑它在定语从句中的成分。
一.指人的关系代词有who、whose、whom、that. 试分析：
The old man who/whom /that we visited yesterday is a famous artist.
Miss Wang is taking care of the child whose parents have gone to Beijing .
The man with whom my father shook hands just now is our headmaster. (=The man who/whom that my father shook hands with just now is our headmaster.)注：
A. 指人时有时只用who不宜用that。
1.先行词为one、ones或anyone
(1)The comrade I want to learn from is the one who studies hard and works hard.
(2)Anyone who breaks the law should be punished.
2.先行词为these时
These who are going to Beijing are the best students of our school.
3.在there be 开头的句子中
There is a student who wants to see you.
4.一个句子中带有两个定语从句，其中一个定语从句的关系代词是that，另一个宜用who，以免重复。
The student that won the first prize is the monitor who works hards.
5.在非限制性定语从句中
A.I met a friend of mine in the street, who had just come from Japan.
B.主句以who开头的句子中,只用that,不用who。
二.指物的关系代词有which、whose(=of which)、that. 试分析：
1. I like the books which / that were written by Lu Xun.
2. The desks (which/that) we made last year were very good.
3. This is the house in which we lived last year. (= This is the house which /that we lived in last year.)
4. I live in the room whose windows face south. (= I live in the room ,the windows of which face south.)
注：
A. 介词如果位于作为其宾语的关系代词之前时，只能用whom、 which不能用who或that.
(1). The girl about whom they were talking is our monitor.
(2). The book in which there are many interesting things was written by Li Ming.
B. 部分短语动词中的介词不可与动词拆开，在定语从句中其介词不可前置，只能放在其动词之后。
Is this the book which she is looking for?
The old man who/whom they are waiting for is Professor Li.
The child who/whom she is looking after is Wang Ping’s son.
C. 指物时，下列情况下只能用that ，不宜用which。
(1)先行词为不定代词，如All、much、anything、everything、nothing、something、none、the one等。
We are willing to do anything that is good to the people.
I have told them all (that) I know.
All that can be done has been done.
(2)先行词是序数词或被序数词、修饰时。
The first book that I read last night was an English novel.
(3)先行词是形容词最高级或被最高级修饰时。
This is one of the most interesting films that I have ever seen.
This is the best that can be done now.
(4)如果有两个或两个以上分别表示人和物的先行词时(先行词既有人又有物)，定语从句的关系代词用which和who都不合适，只能用that。
We know nothing about the doctors and the hospitals that you are talking about.
There are sheep and men that can be seen on the hill.
(5)如果先行词被the only、the very、the last、the same、any、 few 、little、no、 all 、one of、 just修饰时。
This is the only book that can be lent to you.
(6)当主句是以which开头的特殊问句时，关系代词只用that。
Which is the dictionary that he used yesterday ?
D.只物时，下列情况下只能用which，不宜用that。
(1)关系代词放在介词之后
This is the factory in which we once worked.
(2)非限制性定语从句中
This is the book, which is written by Lu Xun.
(3)that，Those作主语时
Those which are on the desk are English books.
E.先行词前有such、the same、 as时, 关系代词用as，不用that, 但the same…as…表示同样的, the same…that…表示同一的
He knows as many people as are present at the meeting.
Such people as you refer to are rare nowadays.
三.比较When/which、where /which、why.
which I still never forget.
This is the day when I joined the party.
which he spent reading the books.
where I found the book.
which makes machines.
This is the place which we once visited.
which I will never forget.
which I am looking for.
限制性定语从句与非限制性定语从句的区别：
限制性定语从句
非限制性定语从句
All the students who study hard have passed.学习努力的学生都考试及格了。(只有努力的及格了，不努力的没及格。) All the students ,who study hard have passed.所有的学生都及格了，他们学习努力。(没有人不及格，这些学生都很努力。)
从句是先行词不可缺少的定语(如去掉，主句意思就不完整或不正确。) 从句是对先行词的附加说明(如去掉，主句意思仍清楚，不受影响。) 与主句关系密切，不用逗号 与主句关系不十分密切，用逗号与主句隔开译为汉语时，从句译在先行词前，与先行词用“的”连接 译为汉语时，从句放在主句后面关系代词that可以代替who、whom(指人)、which(指物) 关系代词不用that,只用who、whom(指人)、which(指物) 关系代词代替宾语时可以省略 关系代词不能省略关系代词as和which
先研究下面两个例句：
○1.This elephant is like a snake, as /which everybody can see. =As everybody can see, this elephant is like a snake. 任何人都看得出来，这头象像条蛇。
○2.Tom didn’t pass the physics exam, which made his parents very angry. Tom物理考试不及格，这使得他父亲很生气。
这两个例句中，as和which所代表的都是整个主句所表示的内容。但有两点不同之处：
1. 在形式上as引导的非限制性定语从句可位于主句的后面，也可位于主句的前面;而which引导的非限制性定语从句只能位于主句的后面，不能位于主句的前面。
2. 在意义上，as引导的定语从句和主句的关系一般为一致关系，常译为“正如……”，“就像……”，而which引导的定语从句和主句的关系是因果关系，或which引导的定语从句是对主句的评论。因此，在意思通顺的情况下，which可代替as，而as许多时候不能代替which，如句○2。再如：
1.He was late again, as / which we had expected. =As we had expected, he was late again. 正如我们所料，他又迟到了。/他又迟到了这是我们早就料到的。
2. The street hasn’t been cleared for weeks, which makes it very dirty. 街道好多星期没有打扫了，因此整条街很脏。(不用as)
3.The young man cheated his friend of much money, which was disgraceful. 那年轻人诈骗了他朋友许多钱财，这是不光彩的。(不 用as)
4.He takes exercise everyday, which has done a lot of good to his health. 他每天运动，这对他的身体很有好处。(不用as)
5.As has already been pointed out, English is rather difficult for a foreigner. 正如已经指出的那样，英语对于初学者说，是相当难学的。在such…as…、the same…as…、 as…、 as many…/much as…等结构中,as不能用which代替。如：
1.Such books as this are too difficult for beginners. 这样的书对于初学的人来说是太难了。
=Books such as this are …
=Books like this are …
2.I live in the same building as he (does). 我和他住再同一座大楼里。
3.He knows as many people as are present at the meeting. 他认识所有到会的人。
4.That day we all got up early as usual. 那天我们和平时一样，都起得很早。
“One of the +复数名词”后面定语从句中谓语单复数情况
这一结构后面的定语从句的谓语动词通常用复数形式，跟定语从句所*近的那个复数名词在数上保持一致。如：
1. That is one of the books that are required for study at school.
2. This is one of the most wonderful novels that have been published since 1990.
3. She is one of the few persons who know Spanish .
4. This is one of the most famous plays that were written in the thirties,
如果one of +复数名词这一结构前面带有the only、the very之类的限定语，后面定语从句的谓语动词则要用单数形式，这是因为定语从句在意义上修饰的是而不是那个复数名词。如：
1.He is the only one of the teachers who knows French in our school.( 修饰the only one)
He is one of the teachers who know French in our school.( 修饰the teachers)
2.This is the only one of the rooms that is free now. (修饰the only one)
This is one of the rooms that are free now. (修饰rooms)
as与which引导的定语从句
两者均可引导非限制性定语从句，有时可以互换，但下列情况多用as。
1. 关系代词引导的定语从句居句首时。 As we all know, the earth is round.
2. 当与such或the same连用时，一般用as。 Such books as you tell me are interesting. I have the same plan as you.
3. 当从句和主句语义一致时，用as，反之则用which。 She has married again, as was expected. She has married again, which was unexpected.
4. as在从句中作主语时，后面常接行为动词的被动语态，如be known，be said，be reported等，如从句中行为动词是主动语态，一般要用which作主语。
She has been late again, as was expected.
Tom has made great progress, which made us happy.
as引导定语从句
as引导定语从句时，既可以引导限定性定语从句，又可以引导非限定性定语从句。区分as引导定语从句和其它从句的关键特征是：as引导定语从句时在从句中做成分，通常做主语或宾语。
1、as引导限定性定语从句
如从句所修饰的名词前有such、the same、as出现，后面的定语从句将由as引导，形成such...as，the same...as，as…as这样的固定结构，译为“和……一样”。
例1：I never heard such stories as he told.
我从未听过他所讲的那样的故事。
例2：He’ll repeat such questions as are discussed in the book.
他将重复书中讨论过的问题。
例3：They made the same mistake as others would have made on such an occasion.
他们犯了和其他人在这种场合下会犯的同样错误as用法详解as用法详解。
2、as引导非限定性定语从句
as引导非限定性定语从句，往往指代一整句话，通常表示“正如”的意思。as引导的非限制性定语从句位置相对比较灵活，可以位于先行词之前、之后或中间。
例：As is known to everybody, the moon travels round the earth.
众所周知，月亮绕着地球转。
as引导时间状语从句
as引导时间状语从句多用于口语，强调“同一时间”或“一先一后”，有时还有“随着”的含义。
例1：As I was going out, it began to rain.
当我出门时，开始下雨了。(as强调两个动作紧接着发生，不强调下雨的特定时间。)
例2：As time goes on, he will understand what I said.
随着时间的推移，他会理解我所讲的话。
as引导原因状语从句
as表示“因为”，与because相比，较口语化，所表达的原因语气较弱，所表的原因比较明显，或是已知的事实。
例1：As the weather is so bad, we have to delay our journey.
因为天气太糟糕，我们不得不推迟旅行。
例2：Any new source of energy will be very welcome, as there is already a shortage of petroleum.
任何新型能源都将大受欢迎，因为石油已经出现短缺。
as引导方式状语从句
as表示“按照”，“以……方式”，“像……一样”，“正如”。
例：Do as the Romans do when in Rome. 入乡随俗
注：as在引导方式状语从句时，还常出现在一个固定的类比结构中：(just) as …, so…。这一句型表示类比，基本含义是“正如……，所以……”。
例：Just as virtue is its own reward, so is vice its own punishment.
善有善报，恶有恶报。
as引导让步状语从句
as可以表示“尽管”，“虽然”，引导让步状语从句，但必须构成倒装。让步状语从句倒装规则有两类：
1、形容词/副词/分词/名词(无冠词)/介词短语等+as+主语+谓语动词，主句。
例1：Much as I like you, I couldn’t live with you.
我尽管很喜欢你，却不能和你在一起生活。
例2：Child as he is, he knows to help others.
尽管他是个孩子，他懂得帮助别人。
2、动词原形+as+主语+助动词(may/might, will/would, can/could, do/does/did)，主句as用法详解考研英语。
例：Try as we may, we cannot sense directly the television signal sent out from the broadcast station.
尽管我们费了很大的劲，也无法直接觉察发射台发出的电视信号
as引导比较状语从句
as引导比较状语从句，其基本结构是as…as。前一个as是副词，后一个as是比较状语从句的连词。否定结构为not so much … as
例1：Small as it is, the ant is as much a creature as are all other animals on the earth.
尽管蚂蚁很小，但是它同地球上的任何其他动物一样，也是一种动物。
例2：It was not so much the many blows he received as the lack of fighting spirit that led to his losing the game.
与其说是他受到了许多打击，还不如说是缺乏斗志使他输掉了比赛。
定语从句知识总结 1
定语从句及相关术语
1.定语从句：修饰某一句中的名词或代词的从句称为定语从句，一般紧跟在它所修饰的先行词后面。被修饰的词称为先行词。
2.关系词：引导定语从句的关联词称为关系词
关系词有关系代词和关系副词。关系代词有that, which, who, whom, whose, as等;关系副词有where, when, why等。
关系词常有3个作用：
1、引导定语从句。
2、代替先行词。
3、在定语从句中担当一个成分。
关系代词引导的定语从句
1.who指人，在从句中做主语
(1)The boys who are playing football are from Class One.
(2)Yesterday I helped an old man who lost his way.
2. whom指人，在定语从句中充当宾语，常可省略。
(1) Mr. Liu is the person (whom) you talked about on the bus.
(2) Mr. Ling is just the boy whom I want to see.
注意：关系代词whom在口语和非正式语体中常用who代替，可省略。
(3) The man who/whom you met just now is my friend.
3. which指物，在定语从句中做主语或者宾语，做宾语时可省略
(1) Football is a game which is liked by most boys.
(2) This is the pen (which) he bought yesterday.
4. that指人时，相当于who或者whom;指物时，相当于which。在宾语从句中做主语或者宾语，做宾语时可省略。
(5) The number of the people that/who come to visit the city each year
rises one million.
(6) Where is the man that/whom I saw this morning?
5. whose通常指人，也可指物，在定语从句中做定语
(1) He has a friend whose father is a doctor.
(2) I once lived in a house whose roof has fallen in.
whose指物时，常用以下结构来代替
(3)The classroom whose door is broken will soon be repaired.
(4)The classroom the door of which is broken will soon be repaired.
(5)Do you like the book whose cover is yellow? (6)Do you like the book the color of which is yellow?
介词+关系代词引导的定语从句
1. 关系代词在定语从句中做介词宾语时，从句常由介词+关系代词引导
(1)The school (that/which) he once studied in is very famous.
(2)The school in which he once studied is very famous.
(3)Tomorrow I will bring here a magazine (that/which) you asked for.
(4)Tomorrow I will bring here a magazine for which you asked.
(5)We’ll go to hear the famous singer (whom/that/who) we have often talk-ed about.
(6) We’ll go to hear the famous singer about whom we have often talked.
2.关系代词前的介词的选择
* 由先行词的习惯搭配或根据先行词的需要。
(1) The speed at which light travels is 300,000 km per second. (at the speed of …以…速度)
(2) The reason for which he didn’t come to school was that he was ill. (for a certain reason 由于某种原因)
* 介词可能是从句短语动词的一个固定部分或固定搭配
(3) Don’t bring children to see the animals of which they are afraid. (be afraid of 害怕)
(4) This is the teacher from whom I borrowed the book. (borrow from…从…借入
注意：
1. 含有介词的动词短语一般不拆开使用，如：look for, look after, take care of等
(1) This is the watch which/that I am looking for. (T)
(2) This is the watch for which I am looking. (F)
2. 若介词放在关系代词前，关系代词指人时用whom，不可用who或者that;指物时用 which，不能用that;关系代词是所有格时用whose
(1) The man with whom you talked is my friend. (T)
(2) The man who/that you talked with is my friend. (F)
(3) The plane in which we flew to Canada is very comfortable. (T)
(4) The plane in that we flew in to Canada is very comfortable. (F)
3. “介词+关系代词”前可有some, any, none, both, all, neither, most, each, few等代词或者数词
(1) He loved his parents deeply, both of whom are very kind to him.
(2) In the basket there are quite many apples, some of which have gone bad.
(3) There are forty students in our class in all, most of whom are from big cities.
关系副词引导的定语从句
1. when指时间，在定语从句中做时间状语
(1) I still remember the day when I first came to the school.
(2) The time when we got together finally came.
2. where指地点，在定语从句中做地点状语
(1) Shanghai is the city where I was born.
(2) The house where I lived ten years ago has been pulled down.
3. why指原因，在定语从句中做原因状语
(1) Please tell me the reason why you missed the plane.
(2) I don’t know the reason why he looks unhappy today.
注意：
1.关系副词引导的从句可以由“介词+关系代词”引导的从句替换
(1) The reason why/ for which he refused the invitation is not clear.
(2) From the year when/in which he was going to school he began to know what he wanted when he grew up.
(3) Great changes have taken place in the city in which./where I was born.
2.当先行词为时间、地点、原因名词时，如果在从句中不是作状语时，不可用关系副词引导。
(1)The reason (that/which) he gave for being late is that his mother was ill.
(2)They make me think of the happy days (that/which) we spent together.
(3)Is this factory the one (that/which) they visited the day before yester- day.
关系代词引导的定语从句
1、由who, whom, that，Whose引导的从句
这些词代替的先行词是人的名词或代词，who作主语指人，whom作宾语指人，that既可作主语又可作宾语(作宾语可以省略)，可以指人也可以指物。Whose 用来指人或物，只用作定语。
(1) Is he the man who/that wants to see you? 他是那个想见你的男人吗?(who/that在从句中作主语)
(2) He is the man whom/ that I saw yesterday. 他就是我昨天见的那个人。(whom/that在从句中作宾语)
(3) The man whom you spoke to just now is our English teacher 你刚刚说话的那个男人是我们的英语老师
(4) he man whose son is a doctor is our professor. 那个儿子是医生的男人是我们的教授。
2、由which, that引导的从句
它们所代替的先行词是事物的名词或代词，在从句中可作主语、宾语等，作宾语时可以省略，例如：
(1) Prosperity which / that had never been seen before appears in the countryside. 农村出现了前所未有的繁荣。(which / that在从句中作主语)
(2) The package (which / that) you are carrying is about to come unwrapped. 你拿那个包裹快要散开了。(which / that在从句中作宾语)
注意： 代表物时多用which，但在下列情况中用that而不用which：
a)先行词是anything, everything, nothing , none等不定代词时;
b)先行词由every, any, all, some, no, little, few, much等修饰时，这时的that常被省略;
c)先行词前有序数词或被形容词最高级修饰时;
d)先行词中既有人又有物时;
e)整个句中前面已有which，who,that时;
f)当先行词为物并作表语时;
g)先行词为one时;
h)先行词同时又被the only,the very,the same修饰时;
关系副词引导的定语从句
1、when指时间在定语从句中做时间状语也可做连接词用 I still remember the day when I first came to the school.
2、where指地点在定语从句中做地点状语 Shanghai is the city where I was born.
3、why指原因在定语从句中做原因状语 ，用在reason 后面。 Please tell me the reason why you missed the plane.
常见考法
对于定语从句的考查，多以单选的形式考查学生灵活运用的能力。一般情况下，常从关系词的意义和功能的角度考查，重点是that,which,who引导的定语从句。
典型例题：Youre the only person ______Ive ever met ______could do it.
A. who B. whom C. whom D. who
解析：先行词person后有两个定语从句,第一个从句省略了关系代词whom.因为, whom作从句中met的宾语,可以省略.第二个从句who could do it.who在从句中作主语,不可省略.
答案：D
误区提醒
当表示时间或地点的名词作先行词时，要判断出它们在从句中作状语还是主语或宾语。作状语时用关系副词，反之用关系代词。
典型例题：I can never forget the day _______ we worked together and the day ______ we spent together.
A. when; which B. which; when C. what; that D. on which; when
解析：. 两个先行词the day都是表示时间的名词,但第一个空白处要填的关系词在从句中作状语,因此要用关系副词when. 第二个空白处要填的关系词在从句中作动词spent的宾语,因此要用关系代词which或that来引导定语从句.
答案：A
定语从句
关系
代词指代例句
who指人,宠物,This is the man who helped me.
whose所有格,
指人,物This is the boss whose name is Michael.
whom宾语, 指人The doctor whom you are looking for
is in the room.
that人,物,
主语或动宾This is the boy that broke the window.
which人,物,The building which is in front of you
主语或介宾 is our school.
I am going to drop out school, （非限）
which makes my parents worried.
关系
副词
when从句时间Do you remember the day
when he came to see you?难点Is Sheba the dog who was killed last year? (指代动物)This is the boss in whose company my farther is working now. (复杂结构)whose = the…of which (P314)There was no one to whom I can turn for help.(复杂结构)of whom (其中) most of whom, none of whom…He is the only person that I want to talk to. (不用which) (P315)作表语: He is no longer the man that he used to be.of which (其中) most of which, none of whichin which case / during which time / at which time 引导从句It was in 1979 that he was elected Chairman.It was 1979 when he was elected Chairman of our club.
I bought the book 2 years ago, since when I have used no others.
Cases are introduced to you
where从句地点why
特殊
as限制性
定语从句
非限制性
定语从句You have reached the point where a change is needed.Tell me the reason why you are late.the same…as (P320)such…as They use such simple words as can be understood by us.as…as (P320)(正如) as is mentioned above as has been reported before
as is often the case as is known to all where you can employ this law.(condition, circumstances, system, example…)I am going to Shanghai where lives my aunt. (从句倒装)I climbed to the top of the mountain, from where I could see thewhole city.先行词只有reasonCan you repeat the reason that you gave yesterday?They use such simple words that we can understand them.(状语从句中，that不担任成分,不可以省略)可以位于句首, 与主语从句区分It is known to all that… (形式主语)As is known to all, (定语从句)What is known to all is that (主语从句)
定语从句知识
定语从句，一个简单句跟在一名词或代词后（先行词）进行修饰限定，就叫做定语从句。在主句中充当定语成分。被修饰的词叫先行词。
一．几个基本概念
1.定语从句的定义：用作定语的从句叫定语从句。
2.先行词：被定语从句所修饰的.名词或代词。
3.定语从句的位置：紧跟先行词（名词或代词）之后。
4.引导词：引导定语从句的词（包括关系代词和关系副词）。
（1）关系代词：that/who/whom/which/as
（2）关系副词：when/where/why
5.引导词的位置：位于定语从句之前（先行词之后）。【as除外】
6.引导词的功能（作用）：
（1）连接先行词和定语从句。
（2）在定语从句中充当一定的成分（关系代词充当主语或宾语，关系副词充当状语）。
7.定语从句的类型：
（1）限定性定语从句（主句和定语从句之间无逗号）。
① 直接由引导词引导定语从句
The man who you’re talking to is my friend.
② 由介词+关系代词（whom/which）引导
The man to whom you’re talking is my friend.
I need a pen with which I can write a letter.
=I need a piece of paper on which I can write a letter.
介词的选用可根据从句中的相关词组确定，该介词通常可以放在关系代词之前，也可放在从句之尾。例如：
The man (who/whom/that) I talked about at the meeting is from Beijing University.
=The man about whom I talked at the meeting is from Beijing University.
The palace (which/that) I often pay a visit to was built in the 17th century.
=The palace to which I often pay a visit was built in the 17th century.
（2）非限定性定语从句（主句和定语从句之间用逗号隔开）。
① 直接由引导词引导定语从句。
② 由介词+关系代词（whom/which）引导。
I live in a house far away from the city, in front of which is a big tree.
There is an apple tree standing at the gate, on which are many apples.
This is the man to whom I gave the book.
③ 由“代词/名词+of+whom/which”或“of which/ whom +名词/代词”(先行词指
人用whom,指物用which)引导。One, some, any, none, all, both, several, many, most, neither, either等词、数词、分数或百分比与of whom或of which连用。
He has five children, two of whom are abroad.
(比较：He has five children, and two of them are abroad.)
We have three books, none of which is/are interesting.
(比较：We have three books, but none of them is/are interesting.)
除why和that不能引导非限定性定语从句外，其余引导词都可以，用法同限定性定语从句一样。但要注意以下区别。
1.在形式上非限定性定语从句与主句有逗号隔开。
2.非限定性定语从句的作用：它只是补充说明先行词的情况，翻译时可译成两个句子。
The engineer, whose leg was badly hurt, was quickly sent to hospital.
（那位工程师被很快送往医院，其腿部受了重伤）
The engineer whose leg was badly hurt was quickly sent to hospital.
（那位腿部受了重伤的工程师被很快送往医院）
3.在非限定性定语从句中，任何引导词都不能省略（包括引导词在此定语从句中充当宾语在内）。指人做主语时只能用who, 做宾语时用whom;
指物做主语，宾语都用which; 关系副词用when或where，也不能省略。
The man, ______ is sitting on the chair, is my father.
The woman, _______ I met yesterday, is my English teacher.
The city, _______ is far away, is very beautiful.
He went to America, ______ his parents live.
He joined the Army yesterday, ______ I left, too.
4.whose引导非限定性定语从句：
The house, whose window faces south, is mine.
=The house, the window of which faces south, is mine.
＝The house, of which the window faces south, is mine.
二.定语从句中关系代词和关系副词的基本用法
1.who/that指人是主格在定语从句中代替先行词，又作定语从句的主语，不能省略。
Do you know the gentleman who/that is sitting there?
2.whom/who/that指人是宾格，在定语从句中代替先行词，又作定语从句的宾语（动宾或介宾）。
① 当作动宾（动词后接宾语）时，关系代词可省略。
Do you know the gentleman (whom/who/that) we met just now?
② 当作介宾（介词后接宾语）时：
介词不提前时，关系代词可省略；
介词提前时，关系代词不可省，即介词＋whom(指人时介词后的关系代词只能用whom)。
The man (whom/who/that) I spoke with is my teacher.
The man with whom I spoke is my teacher.
※注：固定的动词短语（动词+介词）如look for, take care of等不能把动词与介词拆开，既介词不能提至引导词前。
She is the right girl (who/whom/that) we are looking for.
3.whose: 指人或物，是所有格“…的”形式。Whose+n.一起在定语从句中充当主语、宾语（动宾或介宾）即先行词的什么东西怎样了，whose不能省略。Whose+n. = the +n. + of which/whom= of which/ whom+ the =n.
I didn’t find the desk whose leg was broken. （主语）
He is the student whose pencil I broke yesterday. （动宾）
The boss in whose company I work is very kind. （介宾）
4.which/that 指物，指代先行词且在定语从句中作主语或宾语（动宾或介宾）。
① 当作动宾时，关系代词可省略。
② 当作介宾时：
介词不提前时，关系代词可省略；
介词提前时，关系代词不可省，即介词＋which(指物时介词后的关系代词只能用which)。
The house which/that was destroyed in the earthquake is weak.
The pen (which/that) you found yesterday is mine.
The games (that/which) the young men competed in were difficult.
The games in which the young men competed were difficult.
※注:介词+关系代词即介词+whom/which(先行词指人用whom，指物用which)。
定语从句知识总结
定语从句(Attributive Clauses)在句中做定语，修饰一个名词或代词，有时也可以修饰部分或整个句子。
被修饰的名词，词组或代词即先行词。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：who, whom, whose, that, which, as。
关系副词有：when, where, why, how。
关系代词和关系副词放在先行词和定语从句之间，起连接作用，同时又可做定语从句的一个成分。当关系代词做宾语时可以省略。
定语从句中的谓语动词必须在人称上和数量上和先行词保持一致。
定语从句分为限制性定语从句和非限制性定语从句。
关系代词引导的定语从句
1) who, whom, that 这些词代替的先行词是人的名词或代词，在从句中所起作用如下：
Is he the man who/that wants to see you?
(who/that在从句中作主语)
He is the man whom/ that I saw yesterday.
(whom/that在从句中作宾语)
2) whose 用来指人或物，(只用作定语，若指物，它还可以同of which互换).
例如：
Please pass me the book whose (of which) cover is green.
3) which, that 它们所代替的先行词是事物的名词或代词，在从句中可作主语、宾语等.
例如：
A prosperity which / that had never been seen before appears in the countryside.
(which / that在句中作宾语)
The package (which / that) you are carrying is about to come unwrapped.
(which / that在句中作宾语)
关系代词that和which 都可以指物，that 和Who 都可以指人，其用法区别：
不用that的情况：
a) 在引导非限定性定语从句时
(错)The tree, that is four hundred years old, is very famous here.
b) 介词后不能用
We depend on the land from which we get our food.
c) 多用who 的情况
①关系代词在从句中做主语
A friend who helps you in time of need is a real friend.
②先行词为those, people 时
Those who were either fools or unfit for their offices could not see the cloth.
③先行词为all, anyone, ones, one 指人时
One who doesnt work hard will never succeed in his work.
④在There be句型中There is a stranger who wants to see you.
⑤在被分隔的定语从句中
A new teacher will come tomorrow who will teach you German.
⑥在有两个定语从句的句子中，其一用who，其二用that,但若先行词后接两个以上的并列定语从句时，后一个必须重复前一个关系代词。
The student who was praised at the meeting is the monitor that is very modest and studies very hard.
There is a teacher who is always ready to help others and who enjoys what he does.
只能用that作为定语从句的关系代词的情况
a)在不定代词，如：anything, nothing, everything, all, much, few, any, little等作先行词时，只用that，不用which。
All that is needed is a supply of oil.
Finally, the thief handed everything that he had stolen to the police.
b)先行词有the only, the very, the just修饰时，只用that。
He is the very man that helped the girl out of the water.
c)先行词为序数词(the last)、数词、形容词最高级时，只用that。
The first English book that I read was The Prince and the Pauper by Mark Twin.
d)先行词既有人，又有物时。
He talked about the teachers and schools that he visited.
e)当主句是以who 或which 开始的特殊疑问句时，用that 以避免重复。
Who is the person that is standing at the gate.
f)关系代词在从句中做表语
He is not the man that he used to be.
关系副词引导的定语从句
关系副词可代替的先行词是时间、地点、方式或理由的名词，在从句中作状语。
关系副词when, where, why, how的含义相当于介词+ which结构，因此常常和介词+ which结构交替使用.
例如：
There are occasions when (on which) one must yield.
Beijing is the place where (in which) I was born.
Is this the reason why (for which) he refused our offer?
Im surprised the way how (by which) he works out the problem.
注意：
①在非限制性定语从句中，介词+ which结构不能代替关系副词。
如：They set up a state for their own , where they would be free to keep Negroes as slaves.
②含有介词短语的动词一般不能拆开，介词仍放在动词后面。
Is this the book which (that) she was looking for?
3
名词/数词/代词 /形容词最高级 + 介词 + 关系代词引导定语从句
She has written a book , the name of which I have forgotten.
There are fifty-five students in our class , all of whom are working hard.
There are five continents in the world , the largest of which is Asia.
as, which 引导非限定性定语从句的差别
由as, which 引导的非限定性定语从句，as和which可代整个主句，相当于and this或and that。As一般放在句首，which在句中。
As we know, smoking is harmful to ones health.
The sun heats the earth, which is very important to us.
as可引导非限制性从句，常带有正如的意思。
As is know, smoking is harmful to ones health.
用法区别：
(1) as 引导的定语从句可置于句首，而which不可。
As we all know, he never smokes.
(2) as 代表前面的整个主句并在从句中作主语时，从句中的谓语必须是系动词;若为行为动词，则从句中的关系代词只能用which。
(3)非限定性定语从句中出现expect, think, suppose 等表示猜测、想象、预料等时。
She succeeded in her doing the research work , as we expected.
(4)As 的用法 the same? as; such?as 中的as 是一种固定结构, 和……一样……。
I should like to use the same tool as is used here.
We should have such a dictionary as he is using.
定语从句的知识
（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
关系代词和关系副词必须位于从句之首，主句先行词之后，起着连接先行词和从句的作用， 同时在从句中又充当句子成分，高考语法复习四：定语从句。
e.g. She is the girl who sings best of all.（关系代词who在从句中作主语）
The comrade with whom I came knows French.（whom在从句中作介词with的宾语）
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；
3）先行词为人、物时用that ，可作主语或宾语；
4）whose用作定语，可指人或物；
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that用引导。
e.g. Toms 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, anything, nothing, …；
②先行词有最高级修饰，有序数词修饰；
③先行词有only, very, any等词修饰；
④先行词既有人又有物时。
e.g. There is nothing that can prevent him from doing it. 没有什么能阻止他不干那件事。
The first place that they visited in Guilin was Elephant Trunk Hill. 在桂林他们所参观的第一个地方是象鼻山。
This is the best film that I have ever seen. 这部电影是我看过的最好的一部。
Mr Smith is the only foreigner that he knows. 史密斯先生是他认识的唯一的外国人。
2）用which而不用 that的情况：①引导非限制性定语从句；②代表整个主句的意思；③介词 + 关系代词。
e.g. He had failed in the maths exam, which made his father very angry. 他数学考试没有及格，这使他的父亲很生气。
This is the room in which my father lived last year. 这是父亲去年居住过的房子。
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结构中。
e.g. I want the same shirt as my friends. 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
①当主句和从句语义一致时，用as；反之，用which来引导非限制性定语从句。
e.g. He made a long speech, as we expected.
He made a long speech, which was unexpected.
②当非限制定语从句为否定时，常用which引导。
e.g. Tom drinks a lot every day, which his wife doesnt like at all.
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 cant understand.
4. 引导定语从句的关系副词有时可以用"介词 + which"来代替，英语语法《高考语法复习四：定语从句》。
e.g. October 1, 1949 was the day on which ( = when ) the Peoples 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, 口语中也可用who，且可省略。
e.g. The man (whom/ who/ that) you were talking about has come to school.
关于定语从句的知识总结
1. 关系代词用来指代先行词是人或物的名词或代词
句子成分 用于限制从句或非限制性从句 只用于限制性从句
代替人 代替物 代替人或物
主语 Who which that
主语 Whom which that
宾语 Whose(=of whom) whose(=of which)
例1：This is the detective who came from London.
例2：The book which I am reading is written by Tomas Hardy.
例3：The desk whose leg is broken is very old.
例4：This is the room that Shakespeare was born in.
2.关系代词的用法
(1) 如果先行词是all, much, anything, something, nothing, everything, little, none等不定代词，关系代词一般只用that，不用which。例如：
All the people that are present burst into tears.
(2) 如果先等词被形容词最高级以及first, last, any, only, few, mush, no, some, very等词修饰，关系代词常用that,不用which, who，或whom。例如：
(3) 非限制性定语从句中，不能用关系代词that,作宾语用的关系代词也不能省略。例如：
名词性从句：
1.主要包括主语从句，宾语从句，表语从句和同位语从句。一般由that 引起，也可由who, what, when, why, which, whom, whether, how 引起。
2.主语从句很多情况下都可以放到句子后面，而用代词it作形式上的主语。
3.形式宾语
4.由名词性关系代词whatever, whoever, whichever 等引起的宾语从句
5. whether and if 都能引导从句，但用法有所不同。当主语从句直接位于句首时，应用whether,而不用if. Whether 后能直接or not, 但if 不能。
Whether he will come or not is not known.
6.在名词reason后的表语从句必须用that引导，不可误用 because.
The reason why he is often late for class is that he has the bad habit of getting up late in the morning.
定语从句
1.引导定语从句的关系词有who, whom, whose, that, when, where, why and which. 在非限制定语从句中，只可用which, who, whose, where , when., 如果指代前面整个句子， 多用which.
2.当引导定语从句的先行词前有all, any, no, little, much, very first 等词，或先行词前为形容词最高级所修饰时，或先行词为all, anything, nothing, something, everything 时，从句的引导词只能用that.
3.as 可做引导词引导定语从句， 多和such, the same 连用。As 引导的定语从句也可修饰整个句子，既可放在先行词后，也可放在句子开头。
4.介词+which/whom/whose从句
5.代/名+介词+which 从句
6.同位语从句和定语从句
定语从句的关系词
引导定语从句的关系词有关系代词和关系副词，常见的关系代词包括that, which, who（宾格whom,所有格whose）等，关系副词包括where, when, why等。关系代词和关系副词放在先行词及定语从句之间起连接作用，同时又作定语从句的重要成分。
定语从句的分类
根据定语从句与先行词的关系，定语从句可分为限制性定语从句及非限制性定语从句。限制性定语从句紧跟先行词，主句与从句不用逗号分开，从句不可省去，非限制性定语从句主句与从句之间有逗号分开，起补充说明作用，如省去，意思仍完整。
关系代词的用法
1.that 既可以用于指人，也可以用于指物。在从句中作主语或宾语，作主语时不可省略，作宾语可省略。例如：
Mary likes music that is quiet and gentle.玛丽喜欢轻柔的音乐。（that作主语）
The coat （that） I put on the desk is blue.我放在桌子上的那件外套是蓝色的。（that作宾语）
2.which用于指物，在句中作主语或宾语，作主语不可省略，作宾语可省略。例如：
The building which stands near the train station is a supermarket.位于火车站附近的那座大楼是一家超市。（作主语）
The film （which）we saw last night was wonderful. 我们昨天晚上看的那部电影很好看。（作宾语）
3.who， whom用于指人，who 用作主语，whom用作宾语。在口语中，有时可用who代替whom， 也可省略。例如：
The girl who often helps me with my English is from England.经常在英语方面帮助我的那个女孩是英国人。（作主语）
Who is the teacher （whom）Li Ming is talking to? 正在与李明谈话的老师是谁？（作宾语）