用來引導(dǎo)定語從句。它代表先行詞，同時(shí)在從句中作一定的句子成分。
關(guān)系代詞有主格，賓格和屬格之分，并有指人與指物之分，它在先行詞和定語之間起紐帶作用。
主要的關(guān)系代詞有who,whom,whose,which和that。
①who指人，在定語從句中作主語或賓語；
whom指人，在定語從句中作賓語；
whose在定語從句中作定語，其先行詞既可以是人也可以是物。
例如：The teacher who/whom you want to see has come.
②which指物，在定語從句中作主語或賓語。
例如：Here is the coat which will be made to you.
③that多指物，有時(shí)也指人，在定語從句中作主語或賓語。
例如：I have eaten bread that/which he gave to me.
關(guān)系代詞的基本用法：
（1）引導(dǎo)定語從句
關(guān)系代詞代表先行詞，同時(shí)在從句中作一定的句子成分，例如：
The girl whom I spoke to is my cousin. 跟我講話的姑娘是我表妹。
（該句中whom既代表先行詞the girl，又在從句中作介詞to的賓語。）
This is the pencil whose point is broken.這就是那個(gè)折了尖的鉛筆。
(whose 指物，在限定性定語從句中作定語)
He came back for the book which he had forgotten.他重新回來都忘記了他的那本書。
（which指物，在限定性定語從句中作賓語，可以省略）
（2）which為其先行詞。例如：
He said he saw me there, which was a lie.他說在那兒看到了我，純屬謊言。
（3）其他用法
關(guān)系代詞that在從句中作賓語或表語時(shí)可省略， 例如：
I've forgotten much of the Latin I once knew.我過去懂拉丁語，現(xiàn)在大都忘了。
He's changed. He's not the man he was.他變化很大，已不是過去的他了。
注釋：關(guān)系代詞在從句中作賓語時(shí)可省略，that在從句中作表語時(shí)也可省略。
非限定性定語從句中，不能用that作關(guān)系代詞。
關(guān)系代詞的語法注意:
1.常用that 不用which的情況:
①先行詞為all, anything, everything, nothing, something等時(shí)。
I will do all (that) I can to help you.
②先行詞被序數(shù)詞、形容詞最高級(jí)或the only, the very等所修飾時(shí)。
He was the only person that joined the army in his village that year.
③先行詞既有人,又有物時(shí)
They talked about the people and the things (that)they remembered in the school.
④當(dāng)主句是以who 或which開頭的疑問句時(shí), 定語從句用that 引導(dǎo), 以避免重復(fù)。
Who is the boy that was here just now?
2. 若被修飾的名詞充當(dāng)從句介詞賓語時(shí)
介詞可提前于引導(dǎo)詞之前,此時(shí)的引導(dǎo)詞只能用whom 或which.
The pencil with which he was writing broke.
3. 當(dāng)先行詞為way時(shí)
其后的定語從句用in which或 that引導(dǎo),也可不用引導(dǎo)詞。
I don’t like the way (in which/that) he talks to me.
used to/be used to的分別：
①used to + do："過去常常"表示過去習(xí)慣性的動(dòng)作或狀態(tài)，但如今已不存在。
Mother used not to be so forgetful.
②be used to + doing： 對(duì)……已感到習(xí)慣，或"習(xí)慣于"，to是介詞，后需加名詞或動(dòng)名詞。
Scarf is used to taking a walk.(現(xiàn)在習(xí)慣于散步)
③used to 的用法 （否定式簡寫為usedn't） 過去經(jīng)常，以前常常
This used to be a shabby house. （此房年久失修）
used to,would這兩個(gè)詞語都可以表示過去常做某事，有時(shí)可以換用。
used to do 強(qiáng)調(diào)過去習(xí)慣性的行為或狀態(tài)，但是現(xiàn)在沒有這種行為或狀態(tài)了。因此，這個(gè)短語的內(nèi)涵是今昔對(duì)比。
關(guān)系代詞的用法:
一、不用that的情況
在引導(dǎo)非限定性定語從句時(shí) (錯(cuò))The tree, that is four hundred years old, is very famous here.
介詞后不能用We depend on the land from which we get our food.
二、只能用that作為定語從句的關(guān)系代詞的情況
a.在there be 句型中，只用that，不用which。
b.在不定代詞，如：anything, nothing, the one, all, much, few, any, little等作先行詞時(shí)，只用that，不用which。
c.先行詞有the only, the very.（恰恰，正好）.any. few. little. no. all 修飾時(shí)，只用that。
d.先行詞為序數(shù)詞、數(shù)詞、形容詞最高級(jí)時(shí)，只用that。
e.先行詞既有人，又有物時(shí)。
Finally, the thief handed everything that he had stolen to the police.那賊最終把偷的全部東西交給了警察。
三、不能用關(guān)系代詞Which 的幾種情況
1.當(dāng)先行詞為all, little, much, few, everything, none 等不定代詞時(shí)關(guān)系代詞用that而不用which.
There are few books that you can read in this book store.
2.當(dāng)先行詞既有人又有物時(shí)，關(guān)系代詞用that, 不用which.
He asked about the factories and workers that he had visited.
3.當(dāng)先行詞有形容詞最高級(jí)修飾時(shí)，關(guān)系代詞用that, 而不用which.
Guilin is one of the most beautiful cities that I have ever visited.
4.當(dāng)先行詞有序數(shù)詞修飾時(shí)，關(guān)系代詞用that, 不用which.
The first sight that was caught at the Great Wall has made a lasting impression on him.
5.當(dāng)先行詞被the only, the very, the same, the right等修飾時(shí)，關(guān)系代詞用that,不用which.
It is the only book that he bought himself.
6.當(dāng)先行詞被all, every, any, much, little, few, no等修飾時(shí)，關(guān)系代詞用that,不用which.
There is no clothes that fit you here.
7.當(dāng)主句是以which開頭的特殊問句時(shí)，定語從句關(guān)系代詞一般用that而不用which.
Which of the books that had pictures was worth reading?
8.在強(qiáng)調(diào)句型" It is ... that ..." 中,只用that,不用which.
It is in this room that he was born twenty years ago.
9.在" such (the same) ... as ..." 句型中,關(guān)系代詞要用as, 而不用which.
We need such materials as (not which) can bear high temperature.
10.表示" 正如... 那樣 "，" 正象..." 之意時(shí)，用as, 不用which.
Mary was late again, as had been expected.
11.As 引導(dǎo)的定語從句可以放在主句前面，也可以放在主句后面或主句中間，而由 which引導(dǎo)的定語從句只能放在主句后面。
As we all know, oceans cover more than 70% of the earth.
關(guān)系代詞可以省略的情況:
1.關(guān)系代詞which,whom,who,that在定語從句中作賓語時(shí)可以省略。
Here is the man (who/that/whom)you're been looking for.
2.當(dāng)that在從句中作補(bǔ)語時(shí)可以省略。
She is all (that) a teacher should be.
3.在there be 結(jié)構(gòu)中出現(xiàn)定語從句，或在定語從句中出現(xiàn)there be 時(shí)，用作主語的關(guān)系代詞也可省略。
This is the best dictionary (that) there is in the library.
4.狀語的省略
（1）當(dāng)先行詞是reason，而且定語從句中作原因狀語時(shí)，關(guān)系代詞可用why,that,也可以省略。
That is the reason (why) I did it.
（2）當(dāng)先行詞是way,且在定語從句中作方式狀語時(shí)，關(guān)系代詞可用in which,that,也可以省略。
I don't know the way that/ which leads to the top of the mountains.
（3）當(dāng)先行詞是time時(shí)，關(guān)系代詞可用when,that 或省略。
I don't know the exact time (when/that) the sports meet will take place.
注意：關(guān)系代詞作賓語有時(shí)也不能省略。
關(guān)系代詞不能省略情況：
1.在介詞+whom與介詞+which中，whom,which不能省略。
That is the headmaster with whom my father was talking just now.
2.在非限制性定語從句中，作賓語的關(guān)系代詞也不能省略。
The elephant is like a spear,as anybody can see.
3.在the same ...as,such...as,as...as,the same...that中，as,that即使作賓語，也不能省略I have bought the same bicycle as you have (bought). (指同類用as)
This is the same book that I read the day before yesterday. (that指同一個(gè))
4.當(dāng)由and,but,or等連詞連接兩個(gè)或兩個(gè)以上的定語從句修飾一個(gè)先行詞時(shí)，第一個(gè)關(guān)系代詞可省，但第二，第三個(gè)不可省略。
This is the book (which) I read yesterday and which I find very interesting.
關(guān)系代詞格式：
關(guān)系代詞有主格，賓格和屬格之分，并有指人與指物之分。that的用法最廣，that可指人也可指物。
見表：
限定性 | 非限定性 | 限定性 | |
主格 | who | which | that |
賓格 | whom | that | that |
屬格 | whose | of which | of which |
特殊關(guān)系代詞的用法：
關(guān)系詞通常是用來引導(dǎo)定語從句的,但as,than和but這三個(gè)詞卻與which, who, that, where, when和why等典型的關(guān)系詞不同。
三者本身具有常見的字面意義,前面有名詞作先行詞,但后面的定語從句卻不像典型的定語從句。
這些既像連接詞又像關(guān)系詞的詞,我們就姑且稱它們?yōu)闇?zhǔn)關(guān)系詞。
一、as作為準(zhǔn)關(guān)系代詞出現(xiàn)在the same ... as, such ... as, 和as ... as等結(jié)構(gòu)中。
這時(shí), as前面通常要有名詞;
as后面的從句意義上不像是通常的定語從句;
as需要在從句中充當(dāng)一定的句子成分。
1. the same ... as
1) as在從句中作主語
She is the same person as came here last Sunday. 她就是上星期天來這兒的那個(gè)人。
2) as在從句中作賓語
This is the same watch as I lost while I was doing the sightseeing in Shanghai three months ago. 這塊表跟我三個(gè)月前在上海觀光時(shí)丟失的那塊一樣。
3) as在從句中作be動(dòng)詞的表語
China is not the same country as it used to be. 中國已今非昔比。
4) as在從句中作行為方式狀語
You should learn to do housework in the same way as your mother does it. 你應(yīng)該學(xué)會(huì)像你母親那樣做家務(wù)活。
2. such ... as
1) as在從句中作主語
Let children read such books as tend to make them better and brighter. 讓孩子看那些容易讓他們變得更好更聰明的書。
2) as在從句中作賓語
This is not such an interesting book as you just talked about. 這不是你們剛才談到的那種有趣的書。
3) as在從句中作be動(dòng)詞的表語
Such a bad man as he is will be punished. 像他這樣的壞人一定會(huì)受到懲罰。
3. as ... as
1) 第二個(gè)as在從句中作主語
He has as much money as is required. 他要多少錢就有多少錢。
2) 第二個(gè)as在從句中作賓語
I have as many friends as you (do). 我的朋友和你的朋友一樣多。
3) 第二個(gè)as在從句中作be動(dòng)詞的表語
As is known to all, Taiwan is one of the Chinese provinces。眾所周知,臺(tái)灣是中國的一個(gè)省。
二、than作為準(zhǔn)關(guān)系詞 出現(xiàn)在more ... than, less ... than, fewer ... than等結(jié)構(gòu)中。這時(shí), than前面要有名詞; than本身有比較意義,而且需要在從句中充當(dāng)一定的句子成分。
1. than在從句中作主語
Take it easy, I have more money than is needed. 放心，我的錢比所需要的還要多。
2. than在從句中作賓語
I have more/fewer books than you (do). 我的書比你的多/少。
3. than在從句中作be動(dòng)詞的表語
He is a better boy than you (are). 他是一個(gè)比你更好的男孩。
三、but作為準(zhǔn)關(guān)系詞 本身含有否定意義,它前面的主句還有另一個(gè)否定意義。這時(shí)but在意義上相當(dāng)于“who ... not ...”或“which/that ... not ...”。
1.定語從句中有be動(dòng)詞,并將其改為含but的復(fù)合句時(shí), be動(dòng)詞后面不能再有not
There is no one who is not conccrned about his future. (= There is no one but is concerned about his future.) 沒有人不關(guān)心自己的未來?
2. 定語從句中有can, will, shall, must, may, should, ought to等助動(dòng)詞或情態(tài)動(dòng)詞,在將其改為含but的復(fù)合句時(shí),這些助動(dòng)詞或情態(tài)動(dòng)詞后面不能再有not
There is nothing that she can’t do. (= There is nothing but she can do.) 沒有她做不到的事?
3. 定語從句中有助動(dòng)詞do, does, did, 在將其改為含but的復(fù)合句時(shí),應(yīng)去掉do, does, did, 還原其后動(dòng)詞的時(shí)態(tài)及人稱變化
There is no one who doesn’t wish to make great achievements. (= There is no one but wishes to make great achievements.) 誰都希望自己將來能有所成就。
四、which的先行詞：關(guān)系代詞which的先行詞可以是一個(gè)句子
He said he saw me there, which was a lie。他說在那兒看到了我，純屬謊言。
說明：關(guān)系代詞that在從句中作賓語或表語時(shí)可省略
I've forgotten much of the Latin I once knew。 我過去懂拉丁語，現(xiàn)在大都忘了。
相關(guān)初中英語知識(shí)點(diǎn)：定語從句
定語從句：
擔(dān)任定語動(dòng)能的句子稱為定語從句。定語從句在句中的作用相當(dāng)于形容詞，故又稱為形容詞性從句。
定語從句所修飾的詞叫先行詞；定語從句一般用關(guān)系代詞或關(guān)系副詞來引導(dǎo)，關(guān)系詞放在先行詞與定語之間起連接作用，同時(shí)又作從句中的一部分。
定語從句的分類：
根據(jù)定語從句與先行詞的關(guān)系，定語從句可分為限制性定語從句及非限制性定語從句。
限制性定語從句緊跟先行詞，主句與從句不用逗號(hào)分開，從句不可省去;
非限制性定語從句主句與從句之間有逗號(hào)分開，起補(bǔ)充說明作用，如省去，意思仍完整。
1．由that引導(dǎo)的定語從句
一般情況下that可指人或物，可以代替who，whom和which，在從句中作主語或謂語動(dòng)詞的賓語，但不能作介詞的賓語。如：
The comrade that（who）is speaking at the meeting is an advanced worker．
正在會(huì)上講話的那個(gè)同志是個(gè)先進(jìn)工人。
Is this the doctor that（whom）you talked about yesterday？
這就是你們昨天談?wù)摰哪俏会t(yī)生嗎？
The letter that（which）I received yesterday was from my father．
昨天我收到的信是我父親寄來的。
2．由who，whom和whose引導(dǎo)的定語從句
who在從句中作主語，whom在從句中作賓語，whose在從句中作定語。如：
This is the thief who stole my bike．這就是偷我自行車的那個(gè)賊。
He is the boy whom you wanted to find．他就是你想要找的那個(gè)男孩。
The girl whose mother is a doctor is waiting for you outside．媽媽是個(gè)醫(yī)生的那個(gè)女孩在外面等你。
3．由which引導(dǎo)的定語從句
which指物，在從句中作主語或謂語動(dòng)詞的賓語。如：
The book which Mum bought me last week is called“Red Star Over China”．
媽媽上周買給我的那本書名叫《西行漫記》。
The house which Lu Xun once lived in is now the Lu Xun Museum．
魯迅曾經(jīng)住過的那所房子現(xiàn)在是魯迅博物館。
4．由where，when和why引導(dǎo)的定語從句
where在從句中作地點(diǎn)狀語，when在從句中作時(shí)間狀語，why在從句中作原因狀語。如：
I will never forget the day when I joined the League．我永遠(yuǎn)忘不了我入團(tuán)的那一天。
He will go back to the school where he studied next week．下周他要回到他曾經(jīng)學(xué)習(xí)過的學(xué)校。
I don't know the reason why he quarreled with Zhang Lin．我不知道他同張琳吵架的原因。
［注意點(diǎn)］
關(guān)系代詞在定語從句中作賓語時(shí)，關(guān)系代詞常省去。如：
The play（which）I watched just now had been on twice on Channel
我剛才看的那個(gè)戲劇在3頻道上已上演了兩次。
限定性定語從句：
1. that即可代表事物也可代表人，which代表事物；
它們?cè)趶木渲凶髦髡Z或賓語，that在從句中作賓語時(shí)�？墒÷躁P(guān)系詞，which在從句中作賓語則不能省略。
而且，如果which在從句中作“不及物動(dòng)詞＋介詞”的介詞的賓語，注意介詞不要丟掉，而且介詞總是放在關(guān)系代詞which的前邊，但有的則放在它原來的位置
2. which作賓語時(shí)，根據(jù)先行詞與定語從句之間的語義關(guān)系，先行詞與which之間的介詞不能丟
3. 代表物時(shí)多用which，但在帶有下列詞的句子中用that而不用which，這些詞包括all, anything, much等，這時(shí)的that常被省略
4. who和whom引導(dǎo)的從句用來修飾人，分別作從句中的主語和賓語，whom作賓語時(shí)，要注意它可以作動(dòng)詞的賓語也可以作介詞的賓語
5. where是關(guān)系副詞，用來表示地點(diǎn)的定語從句
6. when引導(dǎo)定語從句表示時(shí)間
〔注〕值得一提的是，表示時(shí)間“time"一詞的定語從句只用when引導(dǎo)，有時(shí)不用任何關(guān)系代詞，當(dāng)然也不用that引導(dǎo)
By the time you arrive in London, we will have stayed there for two weeks.
I still remember the first time I met her.
Each time he goes to besiness trip, he brings a lot of living necessities, such as towers, soap, toothbrush etc.
7. whose是關(guān)系代詞，修飾名詞作定語，相當(dāng)于所修飾成分的前置所有格
8. 當(dāng)從句的邏輯主語是some, any, no, somebody, anybody, nobody, something, anything, everything或nothing時(shí)，常用there is來引導(dǎo)
非限定性定語從句
非限定性定語從句的作用是對(duì)所修飾的成分作進(jìn)一步說明，通常和主句間用逗號(hào)隔開，將從句拿掉后其他部分仍可成立
1. which引導(dǎo)的非限定性定語從句來說明前面整個(gè)句子的情況或主句的某一部分
2. 在引導(dǎo)限定性定語從句時(shí)，that有時(shí)相當(dāng)于in which, at which, for which或at which
Attitudes towards daydreaming are changing in much the same way that(in which) attitudes towards night dreaming have changed.
人們對(duì)白日做夢(mèng)的態(tài)度正在改變，這與人們對(duì)夜間做夢(mèng)的看法的變化有非常相似之處。
I like the music for the very reason that(for which) he dislike it.
我出于某種原因喜歡這種音樂，而他恰恰與我相反。
We arrived the day that(on which) they left.
剛好我們到的那天他們走了。
3. 有時(shí)as也可用作關(guān)系代詞
4. 在非限定性定語從句中，不能用that，而用who, whom代表人，用which代表事物
限定性定語從句口訣:
（口訣一）
定語從句真奇妙，
關(guān)系代(副)詞來引導(dǎo)，
定語從句分兩種，
是否限定看逗號(hào)。
（口訣二）
which指物who指人，
地點(diǎn)where時(shí)間when,
that人或物均可，
why之前是reason�！ �
（口訣三）
從句當(dāng)中作賓語，
whom可以代替who,
為了句子更簡練，
關(guān)系代詞可省去�！ �
（口訣四）
關(guān)系若是表所屬，
whose用法不可無�！ �
除此之外還有啥，
whom, which加of。
（口訣五）
關(guān)系代詞不一般，
介詞經(jīng)常用在前，
此時(shí)不用that, who，
which, whom才安全�！�
引導(dǎo)定語從句的關(guān)系詞：
關(guān)系詞 | 詞形 | 所修飾的先行詞 | 在從句中所作的成分 |
關(guān)系代詞 | who | 人 | 主語、賓語、表語 |
whom | 人 | 賓語 | |
which | 物 | 主語、賓語、表語 | |
that | 人或物 | 主語、賓語、表語 | |
as | 人或物 | 主語、賓語、表語 | |
whose=of whom/of=which | 人或物 | 定語 | |
關(guān)系副詞 | when | 時(shí)間詞 | 時(shí)間狀語 |
where | 地點(diǎn)詞 | 地點(diǎn)狀語 | |
why | 原因詞 | 原因狀語 |
關(guān)系代詞的用法：
1. 關(guān)系代詞的句法功能
(1)關(guān)系代詞在句中作主語
例如：I prefer music that/which has great lyrics
(2) 關(guān)系代詞在句中作賓語
例如：I like music that I can sing along with.
(3)關(guān)系代詞在句中作表語
例如：The house is not the one (that) it used to be.
2. 關(guān)系代詞在從句中作名詞的定語
例如：Is she the teacher whose hair is very short?
3. 關(guān)系代詞的用法
(1)who和whom的用法：二者都用于指人。Who在定語從句中作主語、賓語，
whom 在定語從句中作賓語。Whom在從句中能坐介詞的賓語，而who則不能。
例如：
I happened to meet the professor (who/whom) I got to know at a party
in the shopping center yesterday.
(2)whose的用法：一般指人，有時(shí)也指物。在定語從句中作定語。
例如：I have got a friend whose brother is training for the Olymoics.
(3)which的用法：一般指物，在定語從句中作主語、賓語、偶爾作定語。
例如：The photo which we liked best was taken by Zhao Min.
(4)that的用法：指人或物，指人時(shí)可與who、whom互換，指物時(shí)可與that互換。
在從句中可作主語、賓語，還可作表語。
例如：It is a book (that/which) no one really likes.
4. 宜用who不宜用that的情況
(1)先行詞是指人的不定代詞時(shí)
例如：Congratulations to our winners and thanks to everyone who entered the competitions.
(2) 先行詞指人時(shí)且含有較長的后置定語
例如：The boy was crying hard who lost his way while looking for his mother.
5. 在以下情況中，關(guān)系代詞常用that
(1)先行詞為all, little, few, none 及some-, any-, no-與thing所組成的復(fù)合單詞時(shí)，只能用that。
例如：There is nothing that will stop us making progress.
(2)先行詞前有only, some, any等形容詞修飾時(shí)，只能用that。
例如：This is the only problem that we can’t work out.
(3)先行詞前由形容詞的最高級(jí)或序數(shù)詞修飾時(shí)，只能用that。
例如：This is the most interesting book that I have ever read.
(4)先行詞同時(shí)包括人和物時(shí)，只能用他和她，
例如：Lu Xun and his works that we are familiar with are considered great.
6. 只能用which不能用that的情形
(1)當(dāng)非限制性定語從句中的先行詞指物時(shí)，只能用which
例如：The pencil-case, which I bought last week, is missing.
(2)關(guān)系代詞前面有介詞時(shí)，只能用which
例如：The tree under which we used to take a rest has been cut down.
(3)先行詞本身就是that時(shí)
例如：I don’t like that which he did.
關(guān)系副詞的用法
1. when的用法：它的先行詞通常是time, day, morning等。有時(shí)也可和一些介詞一起引導(dǎo)定語從句。
例如：Do you remember the time when she went abroad?
2. where的用法：它的先行詞通常有place, spot, room等。
例如：I like places where the weather is always warm.
3. why的用法：它的先行詞只有reason。Why時(shí)常也可以省略。
例如：Tell me the reason why she was late.
本文來自：逍遙右腦記憶 http://yy-art.cn/chuzhong/258104.html
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