一、定义
定语从句是指在句中做定语作用，修饰句中的名词或代词的从句，其中被修饰的名词或代词为先行词。当关系代词作定语从句的主语时，其后的谓语动词的人称和数取决于先行词的人称和数。
二、定语从句的结构
定语从句一般位于先行词的后面，定语从句由关系代词who, whom, whose, that, which，that, as和关系副词when, where, why等引导。
(一)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做主语时，从句谓语动词的人称和数要和先行词保持一致。
(二)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。
(三)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。
(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。
(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,这时从句谓语动词要用第三人称单数。
(四)介词+关系词
(1)介词后面的关系词不能省略。
(2)that前不能有介词。
(3)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。
(五)as, which引导的非限定性定语从句
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。
定语从句的基本结构3篇扩展阅读
定语从句的基本结构3篇（扩展1）
——定语从句的基本用法3篇
定语从句的基本用法11、当介词放在关系代词之前时。
2、在非限制性定语从句中。
3、当关系代词指整个主句的概念时。
定语从句的基本用法21、when时间状语
注意：It/Ihis/That + be + the first/ second/ last time that… 只能用that,that可以省略，从句用相应的完成时。
2、where 地点状语
注意：当先行词为模糊的地点时，如point. Situation, case, position, stage, scene, spot, activity, family, job等名词时用where.
3、why 原因状语 先行词为reason。
定语从句的基本用法31、介词如何确定
(1)依据定语从句中动词的习惯搭配来确定
(2)依据先行词的习惯搭配来确定
(3)根据意思来确定
(4)为了强调某一名词，不定式前加上关系词
2、关系代词作介词的宾语时，介词的位置
(1)whom和which可以和介词一起放在先行词和从句之间，也可以把介词放在从句中有关动词的后面。
(2)含有介词的短语动词一般不拆开，介词仍放在动词的后面。
(3)关系代词that在从句中作介词宾语时，介词不能放在它的前面，只能放在从句中有关动词的后面。
(4)关系代词whose也可以在从句中与它所修饰的名词一起作介词宾语。
3、“名词/数词/代词+介词+关系代词”结构常见的形式有：名词/one/two/some/none/all/both/several/many/most/a few/a little/the+比较级/the+最高级…+of+which/whom。
定语从句的基本结构3篇（扩展2）
——in which 定语从句3篇
in which 定语从句1你的问题中提到的in which是属于“介词+关系代词”型的定语从句.
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（只用 whom /which）引导
The school (that/which) he once studied in is very famous.
=The school in which he once studied is very famous.
Tomorrow I will bring here a magazine (that/which) you asked for.
=Tomorrow I will bring here a magazine for which you asked.
We'll go to hear the famous singer (whom/that/who) we have often talked about.
=We'll go to hear the famous singer about whom we have often talked.
in which 定语从句21.in which可以等于when,也可以等于where,但不会等于why.
关键是看定语从句中缺少时间状语还是地点状语.
2.例如：
1）I'll never forget these days in/during which I stayed with you.
=I'll never forget these days when I stayed with you.
我永远不会忘记我和你待在一起的日子.
其中：in/during which I stayed with you=when I stayed with you
=I stayed with you in/during which=I stayed with you in/during these days
2）This is the city in which I stayed last year.
=This is the city where I stayed last year.
这就是那个去年我待的地方.
其中：where I stayed last year=in which I stayed last year
=I stayed in which last year=I stayed in the city last year.
3.另外,有的in which找不到合适的关系副词代替.
如：I dislike the way in which you treat me.
我不喜欢你对待我的方式.
其中：in which you treat me=you treat me in which
=you treat me in the way
4.for which=why
如：Can you tell me the reason why you were late?
=Can you tell me the reason for which you were late?
你能告诉我你迟到的原因吗?
其中：why you were late=for which you were late
=you were late for which=you were late for the reason
in which 定语从句3in which用于定语从句，作关系代词，在句中要做成分
in which用于定语从句，作关系副词，在句中不做成分，in which=where
in which只搜索能用在定语从句中，等于where,在定语从句中作状语。
如：He lived in the house in which tomonce lived.
定语从句中如
This is the room in which we stayed
先行词是room，后的句子是用来修饰room的
但是room不可做stay的成分，因为stay是不及物动词，后不可直接家宾语，所以要有个介词.
其实上述的句子
This is the room which we stayed in.
这里的介词是可以提到which前的
定语从句in which等的用法
in which,forwhich,onwhich,atwhich的不同用法
这些都是定语从句里面，由which引导的定语从句，介词提前。
定语从句的基本结构3篇（扩展3）
——定语从句知识基本框架3篇
定语从句知识基本框架1一、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。
二、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。
三、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。
四、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?
他就是想见你的人吗？（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在句中作主语）
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）
五、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. **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，在非正式文体中that常被省略（正式文体中不可省略），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。
六、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。例如：
（错） This is the mountain village where I visited last year.
（错） I will never forget the days when I spent in the countryside.
（对） This is the mountain village (which) I visited last year.
（对） I'll never forget the days (which) I spent in the countryside.
习惯上总把表地点或时间的名词与关系副词 where, when联系在一起。此两题错在关系词的误用上。
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.先行词在从句中作主、定、宾语时，应选择关系代词；先行词在从句中作状语时，应选 择关系副词。
例如：（对）Is this the museum which you visited a few days ago?
（对）Is this the museum where the exhibition was held?
七、从句结构
定语从句公式
定语从句=先行词+关系词+从句
先行词
指被定语从句修饰的名词、代词或句子。
一般先行词出现在定语从句的前面。
关系词
关系词常有3个作用：
①连接作用，连接主句和定语从句。
②指代先行词。
③在定语从句中担当成分。
注：关系代词有主语、宾语、定语之分。一般who做主语或其宾格形式的whom做宾语(whom作宾语时可省略），whose作为定语（whose不可省略）。关系代词在从句中作主语，宾语，定语等，关系副词在从句中作地点状语（where），时间状语（when），原因状语（why）。
定语
定语用来限定、修饰名词或代词，是对名词或代词起修饰、限定作用的词、短语（动词不定式短语、动名词表示的）汉语中常用“……的”表示。主要由形容词担任，此外，名词、代词、数词、分词、副词、不定式以及介词短语也可以来担任，也可以由一个句子来担任。单词作定语时通常放在它所修饰的词之前，作前置定语。短语、从句作定语时则放在所修饰的词之后，作后置定语。
被定语从句修饰的名词、代词称为先行词。如“the girl”，“the book”
如:She is the girl who likes singing. 她就是那个喜欢唱歌的女孩。
这就是一个定语从句。
定语从句知识基本框架2一、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。
二、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。
三、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。
四、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。
延伸阅读：定语从句知识重点与难点
（一）当先行词有最高级，序数词修饰，是不定代词，或是all, no, only等形式时，关系代词一般用that，而不能用which。
1. The Titanic was the largest ship that had ever been built at that time.
2. There is one thing that keeps worrying me.
（二）当先行词是表示时间，地点，原因的词时，关系词用when, where, why 还有which, that
1. I’m very glad to return to my hometown where I had lived for 10 years.
2. This is my hometown which I used to talk about to you.
3. I think I can understand the reason why he didn’t tell the truth to me.
4. No one believes the reason that he gave us about his absence at the meeting.
（三）定语从句的简化表达：
1. The man who is sitting on the platform is a professor from Wuhan University.
2. The letter that was mailed last night will reach him tomorrow.
3. The question that is being discussed is very important.
4. You are welcome to a party to be given in our class at 7:45.
说明：以上的定语从句部分可以用更加简单的非谓语形式表达出来：
1. The man sitting on the platform is a professor from Wuhan University.
2. The letter mailed last night will reach him tomorrow.
3. The question being discussed is very important.
4. You are welcome to a party to be given in our class at 7:45.
说明：修饰一个名词除了后面用定语从句以外，还可以用非谓语动词形式：doing短语，done短语，being done短语，to be done短语修饰。其结构和意思如下：
1. 被修饰名词+doing短语： 正在做….的人/正在发生的事。
2. 被修饰名词+ done短语： 被…..的人/事
3. 被修饰名词+being done短语：正在被…..的人/事
4. 被修饰名词+ to be done短语：将要被…..的人/事
（1）Do you know the man talking to my sister ?
（2）The “crazy” gesture, moving the index finger in a circle in front of the ear, means “you have a phone call” in Brazil.
（3）Did you see that car being repaired ?
（4）In a camera, the lens must be focused on the object to be photographed.
（5）The students to attend the meeting will arrive here tomorrow.
（6）Goods imported from abroad are not always better than those made in China.
（7）The Yellow River, said to be “the mother river” runs across China like a huge dragon.
总结：以上做定语的那些短语就是英语语法中所说的分词，不定式的各种形式作定语。
1. 这些短语作定语应放在被修饰名词的后面。如果单独一个V-ing或V-ed形式作定语，则可以放在被修饰名词前面。
2. 分词作定语时，其动作应与全句动作同时发生。V-ing表示主动意义和正在做，V-ed表示被动意义。being done表示正在被做的
3. 不定式作定语表示将要发生的，to be done表示将要被做的
定语从句的基本结构3篇（扩展4）
——中考英语定语从句3篇
中考英语定语从句1一、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。
二、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。
三、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。
四、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。
定语从句的基本结构3篇（扩展5）
——含有定语从句的文章3篇
含有定语从句的文章1An Ingteresting Trip
I have been to many interesting places in Yiwu,but I have not been to many other parts of China yet.Last month I went to the West Lake where is a famous scenic spot in Hangzhou with my family by bus.
The scenery around the lake was very beautiful.There were many tall trees and beautiful flowers.Some people were walking around the lake and some people were boating on the lake. We played near the lake and enjoyed the beautiful scenery.Each of us lost ourselves in the beautiful scenery.Suddenly it rained.We ran in the rain and we were all wet.But we were very happy.After a while the rain stopped.The sky became very colourful. “How beautiful it is!”I said to myself.
In the afternoon we went back home by train .My trip seemed very short,but my memory of the pleasant trip will last long.
含有定语从句的文章2My Best Friend
I have many good friends,Lily is one of the best.We play together since we two were very young. She is such a pretty girl that when people meet her,they always pat her little head and say,"Oh,how lovely!"Lily is also very brave.I remember one evening two weeks ago,mom sent me to buy some salt and sugar downstair.When I was back on the darksome stairway,I suddenly saw a black shadow behind me,was that a ghost?I was so frightened that I cried "God!"At that very moment,Lily come,she rush at the shadow and shouted to it loudly till it disappeared,then we ran home safely... Maybe you have already get it,yes,Lily is my dog,--my best friend,I love her.
含有定语从句的文章3My Close Friend
Yesterday was April 26. My friend Duan Yankun asked me to have lunch with her family, beacuse it was her birthday. I was very glas, and said "Happy birthday!" to her. We had a good time together.
Her house is not very big, but very beautiful. She told me taht they would soon move into a much bigger house. Her parents are very kind to me. They lead a happy life. They have two cars of their own.
Duan Yankun and I have been good friends since Grade One. I always get on well with her. We help each other. She is pretty, kind and helpful. I like her very much.
定语从句的基本结构3篇（扩展6）
——定语从句关系副词例句3篇
定语从句关系副词例句1一、基本概念：
在复合句中，修饰某一名词或代词的从句叫定语从句。如：
Do you know the man who spoke at the meeting just now?
That is the house where he lived ten years ago.
定语从句所修饰的词叫先行词;定语从句一般用关系代词或关系副词来引导，关系词放在先行词与定语从句之间起连接作用，同时又作从句中的一个成分。
引导定语从句的关系代词有：that, who, whom, whose, which;
关系副词有：when, where, why.
二、关系词的用法：
(一)关系代词的用法：
1. 作主语用who, which和that, 如：
He is the man who/that lives next door.
The train which/that has just left is for Shenzhen.
2. 作宾语用whom, who, which, that, 如：
The man (whom/who/that) we have just seen is a famous writer.
Where is the book (which/that) I bought last week?
注：在非正式文体中，用于指人的关系代词who whom, that 通常可以省略，但在正式文体中通常用whom, 不可省略;用于指物的关系代词which和that 在非正式文体中也通常省略，但在正式文体中一般不省略。
3. 作定语用whose, 如：
(a) He is the man whose car was stolen last week.
(b) It was a meeting whose importance I did not realize at that time.
注：“whose +名词中心词”这一结构在定语从句中既能作主语(如上a句)，又能作宾语(如上b句)。whose 的先行词常用来指人，但有时也可以用来指具体事物或抽象概念，这时可以与of which 结构互换，词序是：“名词+of which”，如：
They came to a house whose back wall had broken down.. (=the back wall of which)
He’s written a book the name of which I’ve completely forgotten. (=whose name)
4. 作表语只用that ，它既可以指人，也可以指物，但时常省略。如：
He is no longer the man that he used to be.
This is no longer the dirty place (that) it used to be.
(二)关系副词的用法：
1.when 指时间，在从句中作时间状语，它的先行词通常有：time, day, morning, night, week, year 等。如：
I still remember the time when I first became a college student.
Do you know the date when Lincoln was born?
注：when时常可以省略，特别是在某些句型和某些时间状语中。如：
Each time he came, he did his best to help us.
But help never stopped coming from the day she fell ill.
2.where指地点，在从句中作地点状语。它的先行词通常有：place, spot, street, house, room,
city, town, country等，如：
This is the hotel where they are staying.
I forget the house where the Smiths lived.
注：where有时也可以省略。如：
This is the place (where) we met yesterday.
3. why指原因或理由，它的先行词只有reason。如：
That is the reason why he is leaving so soon.
注：why时常也可以省略。如：
That is the real reason he did it.
(三) 使用关系副词应注意下列几点：
1. 这三个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. 如：
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. 当先行词是表时间的time, day等和表地点的'place, house等时，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，试比较：
I’ll never forget the day when my hometown was liberated.
I’ll never 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。
定语从句的基本结构3篇（扩展7）
——定语从句用法口诀3篇
定语从句用法口诀1定语从句真奇妙，
关系代(副)词来引导，
定语从句分两种，
是否限定看逗号。
定语从句用法口诀2从句当中作宾语，
whom可以代替who,
为了句子更简练，
关系代词可省去。
定语从句用法口诀3关系若是表所属，
whose用法不可无。
除此之外还有啥，
whom, which加of。
定语从句的基本结构3篇（扩展8）
——托福阅读中的定语从句
托福阅读中的定语从句1在句子中，名词或名词短语主要充当四种成分：主语、宾语、表语和同位语;把句子当作名词来用，分别在另一个句子中做主语、宾语、表语和同位语构成四种从句：主语从句、宾语从句、表语从句和同位语从句。下面，和小编来初步认识一下四种名词性从句的样子。
主语从句
The book is interesting.book 名词作主语;
What I am reading is interesting.完整句 what I am reading 作主语，因此被称为主语从句。该从句有自己的'主语(I)和谓语(am reading)， what 在主语从句中作am reading 的宾语宾语从句。
宾语从句
I believe his words.words 作宾语。
I believe what he said.完整句 what he said 作宾语，因此被称为宾语从句。该从句有自己的主语(he)和谓语(said)，what在宾语从句中作said 的宾语。
表语从句
English is a useful tool.a useful tool 作表语。
The book is what I want.完整句子 what I want 作表语，因此被称为表语从句。该从句有自己的主语(I)和谓语(want)，what在表语从句中作want 的宾语。
同位语从句
I like the book, Gone with the Wind.Gone with the Wind 作book 的同位语。
The mother must accept the fact that her babyis deaf.完整句 that her baby is deaf 作fact 的同位语，因此被称为同位语从句。该从句有自己的主语(her baby)和谓语部分(is deaf)，that 在同位语从句中不充当成分。
