标题：定语从句
定义
复合句中修饰名词或代词的从句，它起定语的作用。
复合句是由一个主句和一个以上的从句而构成的句子。
从句只用作句子的一个成份，起修饰和说明的作用，能独立存在的。　[1]先行词指被定语从句修饰的名词、代词。
一般先行词出现在定语从句的前面。　[1]关系词关系词常有3个作用：
①连接作用，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。
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，whose作为定语（whom，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）。[1]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. 她就是那个爱唱歌的女孩。
这就是一个定语从句。[1]
三种代词引导
关系代词所代替的先行词是人或物的名词或代词，并在从句中充当主语、宾语、定语等成分。关系代词在定语从句中作主词保持一致。1,who, whom, that限定性定语从句中的关系代词
作主语
作宾语
作定语
指人
who/that
whom/that(可省略)
whose
指物
which/that
which/that(可省略)
whose
非限定性定语从句中的关系代词
作主语
作宾语
作定语
指人
who
whom
whose/of whom
指物
which
which
whose/of which
这些词代替指人，whom在定语从句中指人，"who"和“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。在从句中所起作用如下：
（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。（whom在从句中作宾语）
注：who在定语从句中指人，作主语和宾语，作宾语时可省略；做及物动词或介词的宾语，可省略。　[1]2,which、that 用来指物(用作主语、宾语，作宾语时可以省略），例如：
（1）The prosperity which/that had never appeared before took on 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 arecarryingis about to comeunwrapped.你拿那个包裹快要散开了。（which/that在从句中作宾语）
注：which在定语从句中指物，可作主语或及物动词或介词的宾语，作宾语时可省略；that在定语从句中既可指人又可指物，在定语从句中作主语、宾语和表语，作宾语时可省略，指人时，相当于who或whom，指物时，相当于which，作介词宾语时，介词不可提到that前，当介词提前时，需要用which或whom来代替。[1]whose(只用作定语)
“whose”表示谁（可以为人也可以为物）的（东西）
例：A child whose parents are dead is called an orphan.双亲都死了的孩子叫做孤儿。（“whose parents”表示那个孩子的双亲）
He lives in a room whose window faces south.他住的那个房子的窗户是朝南的。（“whose”表示那个房子的窗户）
关系代词：在句中作主语、宾语或定语。
1. that既可代表事物也可代表人，“which”代表事物；它们在从句中作主语或宾语，作宾语可省略“that”在从句中作宾语时常可省略关系词，“which”在从省略。[eg：This is the book （which）you want.]
2.不及物动词+介词”的介词的宾语代词“which”放在它原来的位置。
3. 代表物时多这时的that常被省略；
c）被形容词最高级修饰时；既有人又有物时；
e）整个句中前面已有“which”，“why”行
关系副词：在句中作状语
关系副词=介词+关系代词
why=for which
where=in/ at/ on which（介词同先行词搭配）
when=during/ on/ in/……
1. “where”是关系副词，当然也不用“that”引导。
By the time when you arrived in London, we had stayed there for two weeks. 当你到达伦敦的时候，我们在那里已经待了两个星期。
I still remember the place where I met her for the first time. 我仍然记得我第一次见到她的地方。
Each time when he goes to business trip, he brings a lot of living necessities, such as towels, soap, toothbrush etc。 他每次出差都带来了生活必需品，如毛巾，肥皂，牙刷等其他东西。
2. 当从句的逻辑主语是some, any, no, somebody, anybody, nobody, something, anything, everything或nothing时，常用“there is”开头。
There is somebody here who wants to talk to you. 这里有人要和你说话。
分作进一步说明，通常是引导词和先行词之间用逗号隔开，将从句拿掉后其他部分仍可成立。
三种关系副词
关系副词why关系副词why主要用于修饰表原因的名词（主要是the reason），同时它在定语从句中用作原因状语。如：
We don’t know the reason why he didn’t show up. 我们不知道他为什么没有来。
She didn’t tell me the reason why she refused the offer. 她没跟我讲她拒绝这项工作的原因。
与关系副词when和where不同，why可以换成that或省略。如：
That’s one of the reasons (why, that) I asked you to come. 这就是我请你来的原因之一。
另外，与关系副词when和where可以引导非限制性定语从句不一样，why只能引导限制性定语从句，不能引导非限制性定语从句。如：
他失去工作的主要原因是他喝酒。
误：The main reason, why he lost his job, was that he drank.
正：The main reason why he lost his job was that he drank.关系副词when关系副词when主要用于修饰表时间的名词，同时它在定语从句中用作时间状语。如：
There comes a time when you have to make a choice. 你必须作出抉择的时候到了。
Gone are the days when they could do what they liked. 他们为所欲为的日子一去不复返了。
We’ll put off the picnic until next week, when the weather may be better. 我们将把野餐推迟到下星期，那时天气可能会好一点。
注意不要一见到先行词为时间名词，就以为一定要用关系副词when来引导定语从句，同时还要看它在定语从句中充当什么成分——如果在定语从句中用作时间状语，就用when；如果在定语从句中不是用作时间状语，而是用作主语或宾语，那就不能用when，而要用that, which等。如：
Don’t forget the time (that, which) I’ve told you. 不要忘记我告诉你的时间。
关系代词that / which在定语从句中用作动词told的宾语，正因为是用作宾语，所以也可以省略。关系副词where关系副词where主要用于修饰表地点的名词，同时它在定语从句中用作地点状语。如：
This is the village where he was born. 这就是他出生的村子。
That’s the hotel where we were staying last summer. 这就是我们去年夏天住的旅馆。
Barbary was working in Aubury, where she went daily in a bus.巴巴拉在奥伯里工作，每天得坐公共汽车去上班。
与前面when的情况一样，注意不要一见到先行词为地点名词，就以为一定要用关系副词where来引导定语从句，同时还要看它在定语从句中充当什么成分——如果在定语从句中用作地点状语，就用where；如果在定语从句中不是用作地点状语，而是用作主语或宾语，那就不能用where，而要用that, which等。如：
He works in a factory that [which] makes TV sets. 他在一家电视机厂工作。
关系代词that / which在定语从句中用作主语。
另外注意，where有时还可用于抽象名词后引导定语从句。如：
We have reached a point where a change is needed. 我们到了必须改一改的地步。
There are cases where the word “mighty”is used as an adverb. 在一些情况下，mighty一词可用作副词。
He got into a situation where it is hard to decide what is right and wrong. 他陷入一种难以分辨是非的局面。
I don’t want a job where I’m chained to a desk all day. 我不想找一份整天坐办公桌前的工作。
非限性定语从句
意义：
非限制性定语从句起补充说明作用，缺少也不会影响全句的理解。在非限制性定语从句的前面往往有逗号隔开，如
（1）The house,which I bought last year,has a lovely garden.　我去 年买的的房子带着个漂亮的花园。
（2）This novel, which I have read three times, is very touching. 这本我已经读过三遍的小说很感人。
1.非限定性定语从句可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，例如：
（1）He seems not to have grasped what I meant, which greatly upsets me.他似乎没抓住我的意思，这使我心烦。
（2）Liquid water changes to vapor, which is called evaporation. 液态水变为蒸汽，这就叫做蒸发。
2. 在非限定定语从句中，有时as也可用作关系代词，若as在从句中作主语，其引导的句子可以放在句首，也可以放在句中。例如：
（1）The boy has as much progress as we had expected. 正像我们所预料的那样，这个男孩取得了大的进步。
（2） As everyone knows ,China is a beautiful country with a long history . 每个人都知道，中国是一个有着悠久历史的美丽国家。
3. 在非限定性定语从句中，不能用于在从句中做主语
（1）The boys who are playing football are from Class One. 在踢足球的男孩们是一班的。
（2）I helped an old man who lost his way yesterday . 昨天，我帮助了一个迷路的老人。
限定性定语从句
意义：
限定性定语从句对被修饰的先行词有限定制约作用，使该词的含义更具体，更明确。限制性定语从句不能被省略，否则句意就不完整，例如I met some one who said he know you.
1.在引导限定性定语从句时，that有时相当于in which,at which,for which或on which （1）Attitudes towards daydreaming are changing in much the same way that(in which) attitudes towards night dreaming have changed. 人们对白日做梦的态度正在改变，这与人们对夜间做梦的看法的变化有非常相似之处。 （2）I like the music for the very reason that(for which) he dislike it. 我出于某种原因喜欢这种音乐，而他恰恰与我相反。 （3）We arrived the day that(on which) they left. 刚好我们到的那天他们走了。 2.在限定性定语从句中，当关系代词在从句中担任动词宾语时，关系代词可省略。 （1）The book (that/ which) I am reading is very interesting. 我在读的书很有趣。 （2）Is there anything (which) you wanted? 想要什么东西吗?
限定性从句和非限定性从句的区别
（1）从结构上来看，限定性从句不能用逗号与先行词分开；而非限定性从句却必须用逗号分开。引导非限定性从句的关系代词不能省略。例如：
The clock，which my great-grandfather bought,is still in good order.
这时钟是我曾祖父买的，现 在还是走得很准。
（2）两种形容词性从句往往赋予同一个先行词以不同的含义。例如：
My sister who lives in London is a doctor.
我住在伦敦的妹妹是医生。
My sister,who lives in London,is a doctor.
我的妹妹是一个医生，她住在伦敦。
（3）非限定性从句可以把整个主句当作先行词，而限定性从句没有这种功能。非限定性从句修饰整个主句时，只能用which或as来引导。例如：
I said nothing，which made him still more angry.
我一声不吭，这使他更加生气。
He was a Frenchman,as I could tell from his accent.
他是个法国人，我从他的口音中可以听出来。
He was drunk,which seemed to make a bad impression on the policeman.
他喝醉了，这似乎给警察留下了不好的印象。[2]
先行词和关系词
1）Whoever spits in public will be punished here.（“Whoever”可以用“anyone who”代替）
2）The parents will use what they have to send their son to technical school. （“what”可以用“all that”代替）
但这两句句子已经不是定语从句了，是名词性从句。因为定语从句一定要有先行词，而名词性从句没有。将“Whoever”、“what”分别用“Anyone who”、“all that”代替后，才是定语从句，先行词分别是“Anyone”、“all”。An invitation from her boss, ___came as a surprise.
A. it　B. that　C. which　D. he
答案C。
此为非限定性从句，不能用“that”修饰，而用“which”、“it”和“he”都使后句成为句子，两个独立的句子不能单以逗号连接。况且选“he”句意不通。
2）The weather turned out to be very good, ___ was more than we could expect.
A. what　B. which　C. that　D. it
答案B
英语语法上行不通。
3）It rained hard yesterday, ____ prevented me from going to the park.
A. that　B. which　C. as　D. it
答案B　
“as”和“which”在引导非限宾语。但不同之处主要有两点：
（1）importance to me, as my own is.
在一定的语言环境里，有些名词可以具有形容词的性质。这些名词主要是那些表示人的身份、职业、状态的名词。值得一提的是，在这些具有形容词性质的名词之后，引导定语从句的关系代词不能用“who / whom”。
（2）动词短语先行成分。
这种动词短语既可是限定形式也可是非限定形式。如果是动态动词短语，它们在从句中就一般有限定或非限定形式的替代动词“do”和“as / which”一起代替。“do”可以出现，也可以不出现，但不能用其它动词代替。
（3）句子作先行成分。
这句子可以是整个主句也可以只是主句中的一个从句。有时是连续几个句子，有时甚至可以是一个完整的故事。
二、“as/which”特殊定语从句在句中的位置。
由于先行成分的构成成分”特殊定语从句在句中的位置有以下几种情况：
1. 形容词作先行成分时：形容词的“which”特殊定语从句置于先行成分之后。
2. 动词短语作先行成分时，“as / which”特殊定语从句置于先行成分之后。但是，当从句中含有表示主观意志的插入成分时，“as”特殊。
3. 句子作先行成分时：“as”特殊定语从句的位置较灵活，可以置于先行成分之前、之中或之后。但如果先行成分是直接引语，“as”特殊定语从句与否定词的相对中则常用一些表示“合乎自然规律”、“众所周知”或“经常发生”等意义的词语，如natural, known to all, usual等。
4. 有无状语意要是方式状语意义，而“which”特殊定语从句则无状语意义。“as”特殊定四、关系代词“as”与“which”一词。如：
Freddie, as might be expected, was attending the conference.
1). “Which”作主语时，谓语动词不限，主动被动皆可，只是谓语动词为被动语态时助动词“be”省略。
2). “as”和“which”都可以在特殊定语从句中宾语。
3). “as”和“which”在特殊从句中作补语。如：
We thought him a gentleman, as/which he could never be.
“as”特殊定语从句中可以主谓倒装，“which”从句中则不能主谓倒装。
如果先行成分不是主语补语或宾语补语，关系代词用“which”而不用“as”。如：
He talked like a native, which/as he hardly was.
5."as"用法：
1)."as"引导限制性定语从句
a."such....as"
He is not such a fool as he looks.
I have never heard such a story as he tells.
b."the same ....as"
This is the same book as I lost last week.
(区分"the same...as"与"the same....that"：两者都引导定语从句。that从句中说明的名词与the same修饰的名词是同一个。as从句中说明的名词与the same修饰的名词是同一类，而非同一个。举例：①This is the same pen that I lost. 这支钢笔就是我丢的那一支。②This is the same pen as I lost. 这支钢笔跟我丢的那支笔一模一样。)
c."as...as"
As many children as came were given some cakes.
2)."as"引导非限制性定语从句
常用句式:as is said above 综上所述
as is known to all 众所周知
as is often the case 通常如此
as is reported in the newspaper 如报纸所报道的
6. “which”在特殊从定法
（1）不用that的情况
（a）在引导非限定性定语从句时。
（c）The tree, which 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.
We depend on the land that/which we get our food from.
（2）只能用“that”引导：如先行词被“last,just”修饰时，只用“that”。
（d）先行词为序数词、数容词，又有物时。
（f）先行词指物，在主句中作是“the way”或“the reason”时，“that”可作关系副词，也可省略。
（h）主句的主语是疑问词“who /which”时，避免重复要用“that”．
举例：
Is this the book that you borrowed in the library?
这是你在图书馆借的书吗？
Who that break the window should be punished．
谁打碎了窗户谁该受罚。
All that is needed is a supply of oil.
所需的是石油供应。
The thief gave out everything that he had stolen to the police.
那贼最终把偷的全部东西交给了警察。
定语从句只能“that”引导的情况：
1、先行词是最高级或被最高级修饰。
This is the most interesting book that l have ever read.
2、先行词是序数词或被序数词修饰。
The second foreign country that l expect to visit is Greek.
3、先行词是不定代词时，如"all、few、little、much、anything、nothing、something"
This is the very good dictionary that I want to buy.
4.、先行词既有人又有物时
Can you remember the scientist and his theory that we have learned?
5、先行词被“only”、“the every”、“no”、“one of”等修饰
He is the only person that l want to talk to.
6、在以“which”、“who”、“whom” 引起的问句中，为避免重复，常用"that"
Who is the man that is standing there? Which is the T-shirt that fits me most?
7、“there be”句型中
8、先行词在主句中作表语，或者关系代词本身作从句的表语时宜用“that”
“that”在作宾语时可省略。
（五）区分定语从句和同位语从句
1、定语从句修饰先行词，它和先行词是修饰关系；
同位语从句说明先行词的具体内容，是补充说明的关系。
（1）The boy who is playing football is my classmate.（同位语从句）[3]
2、定语从句由关系代for advice.
（3）The fact that the moon moves around the earth is known to all.
（4）The fact is that the moon moves around the earth.
[定语从句]介词+关系词
1）介词后面的关系副词不能省略。
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。例如：
This is the house in which I lived two years ago. 这是我两年前住过的房子。
This is the house where I lived two years ago.
Do you remember the day on which you joined our club？ 还记得你加入我们俱乐部的那一天吗？
Do you remember the day when you joined our club？
特定选择关系词
只用that不用which1）当先行词是或被序数词，最高级，不定代词修饰时，关系词用that不用which。
2）当先行词既有人又有物时，用that。
3）当先行词带有the only,the very,the same,the last,the one等词时，用that不用which。
4）当主句中有who或which时，为避免重复用that。
5）当先行词为something，anything，nothing，none，no，little，much，all等不定代词时用that。只用who不用that1）如果先行词是those,they,all,persons,people,he,anyone,one时用who不用that。
2）当先行词指人并含有较长的后置定语从句或在被分割的定语从句中时。只用which不用that1）当主句先行词后有介词时，用which。This the one of which I'm speaking。
2）非限定性定语从句，用which。
3) 描述句中一般用which。Beijing，which was China's capital for more than 800years。
4）those +复数名词之后，多用which .Shopkeeper want to keep a number of those goods which sell best。
5）先行词本身是that时。
误区提醒
1）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
2）当主语为物时，不能用what
3）there be句型中，指人用who指物用that。
4）当主句中缺少主语或表语时，用the one。
5）当出现先行词+介词时，关系词只能用whom或which
介词与关系代词
“介词+关系代词”的结构1. “介词+ which”在关系分句中分别可作时间、地点和原因状语，代替相应的关系副词when, where和why。如：　　　　①I still remember the day on which (= when) I first came to school. 我仍然记得初来学校的那一天。　　　　②The factory in which (= where) I work is a large one. 我工作的工厂是一个大厂子。　　　　③This is the reason for which (= why )he was put in prison. 这就是他为什么被关起来的原因。　　　　2. “介词+ which（指物）/whom（指人）”在关系分句中作地点状语，表示存在关系，关系分句主谓常须倒装。如：　　　　①They arrived at a farm house, in front of which sat a small boy. 他们来到一处农舍，前边坐着一个小男孩。　　　　②I saw a man, on the head of whom stood a bird. 我看见一个人，他的头上有一只鸟。　　　　3. “不定代词或数词+ of + which（指物）/whom（指人）”在关系分句中作主语，说明整体中的一部分。如：　　　　　①China has a lot of islands, one of which is Taiwan. 中国有许多岛屿，其中之一是台湾岛。　　　　②There are a lot of students here, none of whom like the film. 这里有许多学生，他们之中无人喜欢这部电影。　　　　4. “介词+ which（指物）/whom（指人）”在关系分句中作目的、方式或地点状语。如：　　　　　①Could you tell me for whom you’ve bought this coat? 你能告诉我这件衣服是给谁买的吗？　　　　②The man, from whom I learned the news, is an engineer. 这人是一位工程师，我是从他那里得到这个消息的。　　　　5. “介词+ which（指物）/whom（指人）”用于被动结构的关系分句中，作状语，说明动作的执行者。如：　　　　　①The wolf by which the sheep was killed was shot. 伤害羊的那只狼被打死了。　　　　②The man by whom the wolf was shot was a good hunter. 打死狼的那人是一个好猎手。　　　　6. “名词+ of which”代替“whose +名词”在关系分句中作定语。如：　　　　　①I saw some trees, the leaves of which (= whose leaves ) were black with disease. 我看见一些树，它们的叶子因害病而发黑。　　　　②He mentioned a book, the title of which (= whose title) I’ve forgotten. 他提到一本书，书名我忘了。　　　　7. “介词+ which（指物）/whose（指人）”修饰后边的名词。如：　　　　①It rained all night and all day, during which time the ship broke into pieces. 雨下了一天一夜，就在这期间轮船撞碎了。　　　　②The driver was the man from whose room she had stolen the maps. 司机就是那个男人，她从他的房间偷走地图。　　　　8. “介词+ which +不定式”。此种用法多见于正文体中，相当于一个带有主语和谓语的定语从句。如：　　　　　She had only 1.87 with which to buy (= she could buy) Jim, her husband, a present. 她只有一元八角七分钱，用这些钱她给丈夫吉姆买一件礼物。分句中分别可作时间、地点和原因状语，代替相应的关系副词when, where和why。如：　　①I still remember the day on which (= when) I first came to school. 我仍然记得初来学校的那一天。　　　　②The factory in which (= where) I work is a large one. 我工作的工厂是一个大厂子。　　　　③This is the reason for which (= why )he was put in prison. 这就是他为什么被关起来的原因。介词的正确选择1. 根据后面动词和介词的搭配关系选择。如：　　　　①This is not the book of which the teacher spoke in class. (speak of 意为“谈论”，相当于talk about)　　　　②The two things of which they felt proud were Jim’s gold watch and Della’s hair. (be / feel proud of 为固定短语，意为“以……自豪”。)　　　　2. 根据前面的名词的搭配关系选择。如：　　　　　①I’ll never forget the day on which I first met him. (表示具体的某一天，介词用on)　　　　②The boy pointed to the direction in which he would run. （“朝……方向”，介词用in）　　　　3. 有时需同时考虑动词和介词的搭配关系及介词和名词的搭配关系。如：　　　　　The clever boy made a hole in the wall, through which he could see what was happening inside the house.
三、介词和关系代词1）介词后面的关系代词不能省略。2）“that”前“Do you”作介词的宾语，且可以省略。例如：（1）The school（that/which）he once studied in is very famous.“that/which”可以省略。= The school in which he once studied is very famous.“which”不可省略。（2）Tomorrow I will bring here 用，如：look for, look after, take care of等。T This is the watch which/that I am looking for.（T=正确）F This is the watch for which I am looking.（F=错误）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）The man famous.（2）I bought many books yesterday, three of which are written by Lu Xun.四、关系代词关系代词（一般情况下）“that”可用在从句做主语，谓动词的宾语，但是不能做介词的宾语。“which”指物，在从句中作主语；“whom”在从句中作宾语；“why”在从句中修语，先行词通常是“the reason”；有时“why”也可用“for+which”代替。例：A doctor who looks after people's health.主语 谓语 先行词 定语从句修饰先行词五、判断介词和关系代词方法一： 用关系代词，还是关系副词完全取决于从句中的谓语动词。不及物动词后面无宾语，就必须要求用关系副词或者是介词加关系代词；而及物动词后接宾语，则要求用关系代词。例如：　This is the mountain village where I stayed last year.　判断改错:（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.　例. Is this the museum ____ the exhibition was held?A. where　B. that　C. on which　D. the one,解析： 主、谓、宾俱全，从句部分为句子的状语表地点，既可用副词where，又因 in the museum词组，可用介词in + which 引导地点状语。而此题中，介词on 用的不对，所以选A。　关系词的选择依据在从句中所做的成分，先行词在从句中做主、宾语时，选择关系代词（who, whom, that, which, whose）； 先行词在从句中做状语时，应选择关系副词（“where”地点状语，“when”时间状语，“why”原因状语）。