定语从句（Attributive Clauses）在句中做定语，修饰一个名词或代词；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等。
关系副词有：when, where, why等。
☆ 关系代词和关系副词的选用取决于先行词及它们在定语从句中的语法成份
关系代词 先行词 在定语从句中充当的语法成份
Who 人 主语
Whom 人 宾语
Whose 人或物 定语
Which 物 主语或宾语
That 人或物 主语或宾语
关系副词 先行词 在定语从句中充当的语法成份
When 表时间的名词 时间状语
Where 表地点的名词 地点状语
Why 表原因的名词 原因状语
That用于表示时间、地点、方式、理由的名词后取代when, where, why和"介词+ which"可作关系副词
1 关系代词引导的定语从句
关系代词所代替的先行词是人或物的名词或代词，并在句中充当主语、宾语、定语等成分。关系代词在定语从句中作主语时，从句谓语动词的人称和数要和先行词保持一致。
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?
他就是你想见的人吗？（who/that在从句中作主语）
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）
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：
They rushed over to help the man whose car had broken down. 那人车坏了，大家都跑过去帮忙。
Please pass me the book whose (of which) cover is green. 请递给我那本绿皮的书。
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. 农村出现了前所未有的繁荣。（which / that在句中作宾语）
The package (which / that) you are carrying is about to come unwrapped. 你拿的包快散了。(which / that在句中作宾语)
☆ 当关系代词在定语从句中充当宾语时，可把关系代词省掉
2 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、地点或理由的名词，在从句中作状语。
1）when, where, why
关系副词when, where, why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. 任何人都有不得不屈服的时候。
Beijing is the place where (in which) I was born. 北京是我的出生地。
Is this the reason why (for which) he refused our offer? 这就是他拒绝我们帮助他的理由吗？
2）that代替关系副词
that可以用于表示时间、地点、方式、理由的名词后取代when, where, why和"介词+ which"引导的定语从句，在口语中that常被省略，例如：
His father died the year (that / when / in which) he was born. 他父亲在他出生那年逝世了。
He is unlikely to find the place (that / where / in which) he lived forty years ago. 他不大可能找到他四十年前居住过的地方。
3 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。及物动词后面无宾语，就必须要求用关系代词；而不及物动词则要求用关系副词。例如：
This is the mountain village where I stayed last year.
I'll never forget the days when I worked together with you.
判断改错
This is the mountain village where I visited last year.
I will never forget the days when I spent in the countryside.
This is the mountain village (which) I visited last year.
I'll never forget the days (which) I spent in the countryside.
方法二： 准确判断先行词在定语从句中的成分(主、谓、宾、定、状)，也能正确选择出关系代词/关系副词。
例1. Is this museum ___ you visited a few days age?
A. where B. that C. on which D. the one
例2. Is this the museum ____ the exhibition was held.
A. where B. that C. on which D. the one
4 限制性和非限制性定语从句
1) 定语从句有限制性和非限制性两种。限制性定语从句是先行词不可缺少的部分，去掉它主句意思往往不明确；非限制性定语从句是先行词的附加说明，去掉了也不会影响主句的意思，它与主句之间通常用逗号分开，例如：
This is the house which we bought last month. 这是我们上个月买的那幢房子。（限制性）
The house, which we bought last month, is very nice.这幢房子很漂亮，是我们上个月买的。（非限制性）
2) 当先行词是专有名词或物主代词和指示代词所修饰时，其后的定语从句通常是非限制性的，例如：
Charles Smith, who was my former teacher, retired last year. 查理史密斯去年退休了，他曾经是我的老师。
My house, which I bought last year, has got a lovely garden. 我去年买的的那幢房子带着个漂亮的花园。
This novel, which I have read three times, is very touching. 这本小说很动人，我已经读了三遍。
3) 非限制性定语从句还能将整个主句作为先行词, 对其进行修饰, 这时as和which代替的是整个主句，相当于and this或and that。As一般放在句首，which在句中。并且从句谓语动词要用第三人称单数，例如：
He seems not to have grasped what I meant, (=and that)which greatly upsets me. 他似乎没抓住我的意思，这使我心烦。
Liquid water changes to vapor, which (=and that) is called evaporation. 液态水变为蒸汽，这就叫做蒸发。
☆ As还在以下几种结构中作关系代词引导定语从句
① the same as : He is just the same as he use to be.他还是和过去一样
② such…as : Such passengers as survived the explosing were drowned.象那些在爆炸中幸免遇难的乘客都被淹死了
③ as…as : As many as we found were taken to the hospital.我们找到多少就送到医院
☆关系代词that和关系副词why不能引导非限制性定语从句。
5 介词+关系词 (介词前置：关系代词如果在定语从句中充当介词的宾语，可把介词前置到关系代词的前面，形成介词+关系代词的结构)
1）介词后面的关系代词不能省略。
2）that前不能有介词。
3）如果关系代词是动词短语的宾语，动词短语的介词不能前置
错误用法：This is the girl of whom he will take care.
正确用法：This is the gril whom he will take care of
4）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?
☆另外还应注意的是:
①way后常用that代替in which，也可省略that
I really don't like the way (that) he talks.
That was the way in which the old lady looked after us.
②of which起形容词的作用，相当于whose（用来指物）
They live in a house whose door (the door of which) opens to the south.
③相同的先行词在表示不同的含义时，要根据其含义用不同的介词。
I can't remember the age at which he won the prize.我记不起他获得奖金的年纪
That is the age in which people live in peace and happiness. 那正是人们生活在和平幸福的时期
age在前句中意为"年岁"，与at搭配，在后句中意为"时期"，与in搭配。
④先行词或定语从句中的动词、形容词要根据不同的具体语境选择适当的介词。 This is the bus on which the accident happened. 这是发交通意外的那辆巴士
This is the bus by which I came to this town. 这是我搭程去镇上的巴士
6 Which和that 的选用
1）当先行词是不定代词(everything , something , anything , littlt , much)时，只能用that
Is there anything that I can help you? 有什么我可以帮你的吗？
2)当先行词被序数词所修饰时，只能用that
This is the second book that was written by the writter. 这是那个作者写的第二本书
3)当先行词被形容词的最高级修饰时，只能用that
This is the best film that I have ever seen. 这是我所看过的最好的电影
4)当先行词前有限定词(or , every , a few , noly , some , very等)修饰时，只能用that
This is the only film that I wanted to see. 那正是我唯一想看的电影
5）在there be句型中，只用that，不用which
6）先行词既有人，又有物时，只能用that
5)当介词前置时，只能用which(P5-2)
6)在非限制定语从句，只能用which(并在前用 ，号与主句隔开)
7 But引导的定语从句相当于一个否定从句
There is no one but knows about the matter. 没有人不知道这事
8定语从句和同位语从句的区别
1）同位语从句与前面的名词是同位关系，即说明它前面名词的内容；而定语从句与前面的名词是修饰与被修饰关系，即限定它前面的名词范围，或补充一些情况。
The news that l hove passed the exam is true．我通过了考试这一消息是真的。（同位语从句，即从句所表达的意思就是前面名词的内容。）
The news that he told me just now is true．他刚才告诉我的消息是真的。 （定语从句，从句对前面名词起修饰限制作用，即“他告诉我的”那个消息，而不是别的消息。）
2) 引导同位语从句的that是连词，在从句中不充当任何成份，而引导定语从句的that是关系代词，除起连接作用外，还在从句中充当主语、宾语或表语等。如：
The idea that computers can recognize human voices surprises many people. 计算机能够识别人的声音的想法使许多人感到惊奇。（that在从句中不充当任何成份。）
The idea that he gave surprises many people． 他提出的观点令许多人感到吃惊。 （that在从句中作gave的宾语。）
定语从句练习
1易混易错定语从句练习
有些定语从句方面的题，如果不仔细审题、不弄清句意和句子结构，就很可能把一些似是而非的东西搞混，从而降低解题的准确性。要想解决这个问题就得从准确理解句意和理清句子结构入手。
1．①Who lives in the house ＿＿＿ windows face south？
② Who lives in the house ＿＿＿ the windows face south？
A．whose B．which C．of which D．that
解析：答案是①A②C。在句①中windows前没有定冠词，它所缺的是定语形容词，而whose的用法就是在定语从句中作定语且既可指人也可指物。在句②中windows前有定冠词，所以要填的内容不能作前置定语，又因为“房子的窗户”用英语表达是“the windows of the house”，故可用of which引导定语从句。
2．①Is this factory ＿＿＿ you visited last year？
②Is this the factory ＿＿＿＿＿＿you visited last year？ A．that B．of which C．the one D．wher
解析：答案是①C②A。在句①中factory前没有定冠词，这说明this是作它的定语。这样，句中就缺少表语，也就是说定语从句缺少先行词，故选C（the one后省略了that）。在句②中this作主语，the factory作表语，其后带一个that引导的定语从句，故选A
3．①John is the only one of the students who＿＿＿French．
②John is one of the students who ＿＿＿ French．
A．know B．knows C．knowing D．known
解析：答案是①B②A。在句①中的句意是“约翰是学生中唯一懂法语的那个学生”，其重心是the only one故从句谓语动词应与one一致。在句②中的句意是“约翰是懂法语的学生中的一个”，也就是“懂法语的学生不止一个，约翰只是其中之一”，其重心是the students，故从句中谓语动词应与students一致。
4．①When I have trouble，he is the only one ＿＿＿I can ask for help．
②When I have trouble，he is the only one ＿＿＿I can go for help．
A．whom B．to whom C．which D．to who
解析：答案是①A②B。句①中，在结构上所要添的内容在从句中作ask的宾语其句式是ask sb．for sth．，故用whom引导定语从句。在句②中，go是不及物动词其句式是go to sb．for sth．，故用to whom引导定语从句。
5．①This is the knife ＿＿＿I usually cut my pencil．
②This is the knife ＿＿＿I usually use to cut my pencil．
A．with which B．which C．by which D．with that
解析：答案是①A②B。在句①中，定语从句的句式是cut my pencil with the knife，故用with which引导定语从句。在句②中，定语从句的结构是use the knife to cut my pencil，故用which引导定语从句。
6．①Last summer he went to Beijing，＿＿＿ he had visited twice．
②Last summer he went to Beijing，＿＿＿ he visited a lot of places of interest．
A．which B．where C．that D．there
解析：答案是①A或B②B。在句①中，所要填的内容在定语从句中应作visited的宾语，故应填关系代词which或that。在句②中，所要填的内容在定语从句中作地点状语，故应填关系副词where。 7．①He still remember the days ＿＿＿we spent together．
②He still remember the days ＿＿＿we spent the summer holidays together．
A．which B．when C．where D．that
解析：答案是①A②B。在句①中，所要填的内容在定语从句中应作spent的宾语，故应填关系代词which。在句②中，所要填的内容在定语从句中作时间状语，故应填关系副词when。
8．①The reason ＿＿＿ he gave us was that his car broke down on the way．
②The reason ＿＿＿ he was late was thathis car broke down on the way．
A．why B．which C．how D．what
解析：答案是①B②A。在句①中，所要填的内容在定语从句中应作gave的宾语，故应填关系代词which。在句②中，所要填的内容在定语从句中作原因状语，故应填关系副词why。
2高考真题练习
1. (’03北京24)York, ________ last year ,is a nice old city.
A. that I visited B. which I visited C. where I visited D. in which I visited
【解析】 考查非限制性定语从句。是用关系代词或者是用关系副词引导定语从句，要根据他们在定语从句中的成份来确定，visit是及物动词，后面需要用关系代词作宾语，排除C，D。that 不用于非限制性定语从句中，排除A。答案为B。
2.(’03上海41)I can think of many cases _________ students obviously knew a lot of English words and expressions but couldn't write a good essay.
A. why B. which C. as D. where
【解析】 考查定语从句。此句的先行词是many cases，单看从句与先行词的关系应是：students obviously knew a lot of English words and expressions but couldn't write a good essay in many cases.因此应用in which或where引导定语从句，备选答案中没有in which，于是选where。答案为D。
3. (’03上海44)There is a new problem involved in the popularity of private cars _________ road conditions need_________.A. that ...to be improved B. which...to be improved C. where ...improving D .when...improving
【解析】 考查同位语从句。因为先行词在从句中不作任何成份，因此用关系词that，故B、C、D均不正确。对于第2个空，need既可作实义动词，又可作情态动词。作实义动词时后跟动词不定式，即need to do sth，另外 road conditions与improve之间是被动关系，因此是need to be improved(need to be done=need doing)。译文：私家车受欢迎所涉及到的新问题是道路状况需要改善。答案为A。
4.(’03北京春季31)We are living in an age ________ many things are done on computer.
A. which B. that C. whose D. when
【解析】 这是定语从句，先行词是age,表时间，所以用when引导。答案为D。
5.(’03安徽春季24)People have heard what the President has said; they are waiting to see _________he will do.
A. how B. what C. when D. that 【解析】 考查宾语从句。what引导宾语从句，在从句中作do的宾语。排除A、C、D。答案为B。
6.(’03上海春季32)_________ has been announced ,we shall have our final exams next month.
A. That B. As C. It D. What
【解析】 as引导定语从句表示“正如……”，并非某个名词或代词是先行词，而是整个主句所表达的内容是定语从句所修饰的。译文：正如所宣布的那样，下月我们将进行期末考试。答案为B。
7.(’02北京22)We will be shown around the city :schools ,museums ,and some other places, ________ other visitors seldom go. A. what B. which C. where D. when
【解析】 这是一个定语从句，先行词是places，表示地点，非限定性定语从句中缺少状语，因此用where来引导定语从句，故要填where。译文：我们被带领着参观了这座城市：学校、博物馆和其他一些游人很少去的地方。答案为C。 8.(’02上海31)Alec asked the policeman _______ he worked to contact him whenever there was an accident.
A. with him B. who C. with whom D. whom
【解析】 这是一个定语从句，the policeman是先行词。work是不及物动词，“work with sb”意为“与某人共事”，所以定语从句应为with whom he worked。译文：无论何时发生事故时，Alec要求与他一起工作的警察与他联系。答案为C。
9.(’02上海35)There's a feeling in me _______we'll never know what a UFO is-not ever.
A. that B. which C. of which D. what
【解析】 同位语从句that we'll never know what a UFO is-not ever作a feeling的同位语，解释a feeling的具体内容。that连接同位语从句时，只起连接作用不作从句的任何成分。译文：我有一个这样的感觉，我们不会知道什么是UFO--永远不会。答案为A。
10.(’02京、蒙、皖春季35)The famous basketball star, ______tried to make a comeback, attracted a lot of attention.
A. where B. when C. which D. who
【解析】 先行词是The famous basketball表示人，非限定性定语从句中缺少主语，因此要填who。who在定语从句中作主语。答案为D。
11.(’02上海春季35)Is this the reason _______at the meeting for his carelessness in his work?
A. he explained B. what he explained C. how he explained D. why he explained
【解析】 the reason后接定语从句。因为先行词the reason作explained的宾语，用that或which引导定语从句在从句中作宾语时省略。译文：这就是他在会议上对他为什么在工作上粗心大意的理由所作的解释吗?答案为A。
12.(’01全国22)The film brought the hours back to me_________I was taken good care of in that far-away village.
A. until B. that C. when D. where
【解析】 when引导定语从句(the hours的定语)，修饰先行词the hours,when在从句中作状语。译文：这部电影使我回忆起我在那偏远的村庄得到无微不至的照顾的时光。答案为C。
13.(’01上海35)Information has been put forward ________ more middle school graduates will be admitted into universities. A. while B. that C. when D. as
【解析】 这是一个同位语从句。that引导从句作information的同位语，解释information的具体内容。注意：that和what引导名词性从句(主语、宾语、表语和同位语从句)的区别：that引导名词性从句，只起引导作用，在从句中不作成分。that引导宾语从句时，that可省略，而在其他三个从句中，that虽不作成份，一般也不省略；what在这四个名词从句中一定作成分，作主语、宾语、表语或补语。译文：有消息说，更多的中学毕业生将进入大学。答案为B。
14.(’01上海37)He's got himself into a dangerous situation ________ he is likely to lose control over the plane.
A. where B. which C. while D. why
【解析】 这是一个定语从句。先行词是a dangerous situation。因为situation的意思是“位置”，所以要填where。译文：他已陷入飞机似乎失去控制的危险境地。答案为A。
15.(’01京、蒙、皖春季11)John said he’d been working in the office for an hour, ______was true.
A. he B. this C. which D. who
【解析】 考查非限定性定语从句。which引导非限定性定语从句，修饰整个主句所表达的内容。答案为C。
16.(’01上海春季30)Have you seen the film “Titanic”, ________leading actor is world famous?
A. its B. it's C. whose D. which
【解析】 这是一个定语从句，因为先行词the film “Titanic”和leading actors是所属关系，所以要填写whose。答案选C。
17.(’00全国17题)Dorothy was always speaking highly of her role in the play, _________,of course , made the others unhappy. A．who B．which C．this D．what
【解析】 这是一个非限制性定语从句，which指代Dorothy夸大自己在剧中角色的作用这件事。答案选B。
18.(’00上海28)Recently I bought an ancient Chinese vase, ________ was very reasonable. A. which price B. the price of which C. its price D. the price of whose
【解析】 这是一个非限定性定语从句。根据句意可知是花瓶的价格。在定语从句中表示“谁的”，可以这样表达，如：I live in the room whose windows face south(名词前没有冠词，用whose)=I live in the room the windows of which face south(如果名词前有冠词就用of which)，答案为B。
19.(’00上海30)She found her calculator ________ she lost it.
A. where B. when C. in which D. that
【解析】 这是一个地点状语从句，意思是“东西是在丢的地方找到的。”in which用于定语从句中，其前必须有先行词。这个句子中没有先行词，所以不能填in which。答案为A。
20.(’00上海35)Greenland, ________island in the world, covers over two million square kilometres.
A. it is the largest B. that is the largest C. is the largest D.the largest
【解析】 有些考生把这个句子理解成了定语从句，误选了选项B。如果这是非限制性定语从句，必须用关系代词which引导，而不用that，即which is the largest islad in the world。实际上，the largest island in the world作Greenland的同位语。答案选D。
21.(’00京、皖春季10)The result of the experiment was very good, ________we hadn't expected.
A. when B. that C. which D. what 【解析】 这是一个非限制性定语从句，which在定语从句中作hadn't expected的宾语。这句话的意思是“实验的结果很好，是没有预想到的”。答案选C。
22.(’00京、皖春季16)It was an exciting moment for these football fans this year,________for the first time in years their team won the World Cup.
A. that B. while C. which D. when 【解析】 根据句子的结构可以排除that和which。再根据所提供的情境It was an exciting moment可以看出是一个时间状语从句。注意：while的意思是during the time that表示一段时间内；when的意思是of that time that表示某个时刻，与an exciting moment相对应。这句话的意思是“当他们的队首次进入世界杯时，对于这些足球迷来说是今年的一个令人激动的时刻”。答案为D。
23.(’99年全国19)Carol said the work would be done by October, ________personally I doubt very much.
A. it B. that C. when D. which 【解析】 在这个非限制性定语从句中，关系代词which代替Carol所说的话。这句话的意思是“Carol说工作将在十月完成，我个人对此表示怀疑。”答案选D。