(本文選自《魔方英語語法》第十一章第四節(jié)。已經(jīng)登記版權(quán),，請勿用于商業(yè)用途,。)

英語中的定語從句是難點，也是考試熱點,。

什么是定語從句,？修飾名詞/代詞的從句叫做定語從句。被修飾的名詞/代詞叫做先行詞,。

如,，This is the boy who won the first prize.（This is the boy.是主句。who won the first prize是定語從句,。the boy是先行詞,。who是引導詞。）

一. 定語從句原理

學習定語從句,，首先要搞清楚把簡單句變?yōu)槎ㄕZ從句的三個步驟,。

其次，在此基礎(chǔ)上,，搞清楚定語從句的先行詞與引導詞的三種關(guān)系,。

最終，把以上兩塊內(nèi)容匯總為“定語從句的先行詞與引導詞總表”,。

下邊具體講解,。

1.如何把簡單句變?yōu)槎ㄕZ從句？分為三個步驟：同指,，替換,，前移。

①同指,。找出兩句中指代同一事物的名詞或代詞,。（并根據(jù)句意確定該把哪句變?yōu)槎ㄕZ從句）,。

②替換。用疑問詞替換這個名詞/代詞（或含有這個名詞/代詞的結(jié)構(gòu)）,。

③前移,。把疑問詞（或含有疑問詞的結(jié)構(gòu)）提前到句首。

例句（兩個簡單句變?yōu)椤爸骶?定語從句”）

Step①This is the house. He lived in the house. （兩個簡單句）

Step②This is the house. He lived in which （替換the house）

Step②This is the house. He lived where （替換in the house）

（可見,，可以替換名詞,，也可以替換“介詞+名詞”）

Step③This is the house which he lived in. （把which提前）

Step③This is the house in which he lived. （把in which提前）

（可見，可以把代詞提前,，也可以把“介詞+代詞”提前）

Step③This is the house where he lived. （把where提前）

（可見,，先行詞是名詞時，引導詞可能是代詞,，也可能是副詞,，這得根據(jù)所作成分而定。）

2.先行詞與引導詞的三種關(guān)系,。先行詞（不管是名詞還是代詞）,，總是名詞性的，而相應的引導詞則有三種可能：名詞性代詞,，形容詞性代詞，副詞,。見下表,，

為什么有時先行詞與引導詞的詞性不對等呢（如，先行詞是名詞,，而引導詞是副詞）,？因為，類似于“對劃線部分提問”,，對含有名詞的結(jié)構(gòu)提問,，而非對名詞提問。如,，先行詞是the house,，對the house 提問，則引導詞用which,，對含有名詞的結(jié)構(gòu)in the house提問,，則引導詞用where。所以,，引導詞并非只代替名詞,，而是代替名詞或含有名詞的結(jié)構(gòu)。分為三種情況：①名詞,，用代詞代替,。②“介詞+名詞”,，用副詞代替。③名詞所有格,，用whose代替,。本節(jié)的二/三/四/五/六，其實反復講的就是這個意思,。

例句（先行詞與引導詞的三種關(guān)系）

●①This is the house.He lived in the house.→This is the house which he lived in.（引導詞是名詞性代詞）（對名詞提問,。he lived in the house→he lived in which→which he lived in）

●②This is the house.The house’s roof is under repair.→This is the house whose roof is under repair.（引導詞是形容詞性代詞）（對名詞所有格提問。the house’s roof is under repair→whose roof is under repair）

●③This is the house.He lived in the house.→This is the house where he lived.（引導詞是副詞）（對介詞短語提問,。he lived in the house→he lived where→where he lived）

3.定語從句的先行詞與引導詞總表（注1）,。匯總1和2的講解，可得,，

注1.此表也可以叫定語從句的引導詞總表,，為了強調(diào)先行詞與引導詞的關(guān)系，才加了“先行詞與”這幾個字,。注2. 先行詞（不管是名詞還是代詞）,，都是名詞性的。注3. when等是副詞,，“介詞+whom/which”（介詞短語）是副詞性結(jié)構(gòu),。注4. 一般地，定語從句的引導詞都是由疑問代詞/副詞轉(zhuǎn)換而來的,，但是,，有些詞不是由疑問代詞/副詞轉(zhuǎn)換而來的，如,，that和as,。that將在第四節(jié).六.講解。as在表中未列出,，將在第四節(jié).七.講解,。

整個第四節(jié)（共22頁）都是在此表基礎(chǔ)上展開的。此表的關(guān)鍵在于：不是“一個先行詞對應一個引導詞”,，而是“一個先行詞對應多個引導詞”（簡稱“不是一對一,，而是一對多”）。到底該用哪個引導詞呢,？由引導詞在從句中作什么成分決定,。

4.如何選擇定語從句的引導詞？綜上所述,，應該“先看詞性后看詞義”,。具體地，①看詞性，也就是看引導詞在從句中作什么成分,。②看詞義,，也就是看引導詞指代哪個先行詞。如,，指人還是指物,。

有些同學習慣于從“指人/指物”入手選擇引導詞。這種做法不能說錯誤,，但是其作用十分局限,。因為，①從上邊的“先行詞與引導詞總表”可以看出,，通過“指人/指物”,，只能辨析“who(m)/which”。②僅以先行詞“指人”的情況看,，其對應的引導詞就有四個,。到底該用哪種，要通過“詞性”來判斷,。

例句（根據(jù)詞性選擇引導詞）

He is the man who/that bought a book for me.（作主語應該用代詞主格）

The boy who(m)/that his father bought a book for is Bob.（作賓語應該用代詞賓格）

The boy whose father bought a book for him is Bob.（作定語應該用物主代詞）

They visited the town where I lived.（作狀語應該用副詞）

They visited the town which/that I liked.（作賓語應該用代詞）

5.從定語從句原理可以直接推導出本節(jié)的第二至五小節(jié)的絕大多數(shù)內(nèi)容,。

二.who(m)/which引導定語從句

如上頁的“先行詞與引導詞總表”所示，who(m)指人，which指物，that指人或物，它們在定語從句中作主語/賓語/表語,。（鏈接：關(guān)于that引導定語從句以及that/who(m)/which對比，將在本節(jié)第六小節(jié)集中講解。）

1. who(m)/which引導定語從句,。

●Lining now is a successful entrepreneur. Lining used to be a player.

→Lining who used to be a player now is a successful entrepreneur.

●The 17th Asian Games was held in Incheon. Incheon lies in the northwest of South Korea.

→The 17th AG was held in Incheon which lies in the northwest of SK.

2.引導詞在定語從句中作主語時，從句的謂語應該與先行詞保持一致,。

這是因為,，who/which/that等本身既可能是單數(shù)又可能是復數(shù)，如,，who is/are,，which is/are，或that is/are,，從引導詞本身看不出來單/復數(shù),，但是它們復指前邊的先行詞（引導詞=先行詞），所以,，此時可以從先行詞看引導詞到底是單數(shù)還是復數(shù),。如，

●People who are nearsighted can only see things that are very close to their eyes.

近視的人只能看到離他們眼睛很近的東西,。

●I, who am your teacher, will try my best to help you.我—是你的老師,，將全力幫你,。

●He is one of the students who have passed the exam.他是通過考試的一個學生。

（one of+名詞復數(shù)+who+謂語復數(shù),。主謂一致,，可參看第二章第六節(jié)。）

●He is the only one of the students who has passed the exam.他是唯一通過考試的學生,。

（the only one of+名詞復數(shù)+who+謂語單數(shù),。）

分組對比練習

題組15（把定語從句還原為簡單句，并以此確定其引導詞）

1.This is the school____I once studied.

2. This is the school____is the most famous the city.

3. I am studied at a school____my father teaches English.

還原為陳述句：I once studied at the school. The school is the most famous in the city. My school teaches English at the school. 根據(jù)對劃線部分提問的規(guī)則,，第1和3小題填where,，第2小題填寫that/which。

題組16（引導詞作主語時,，定語從句中謂語的數(shù)）

1. She is one of the few girls who _____ in the kindergarten. (1994,上海)

A. is well paid B.are well paid C.is paying well D.are paying well

分析：one of+名詞復數(shù)+who+謂語復數(shù),。選B

2. Barbara is easy to recognize as she's the only one of the women who _____ evening dress.(2010,全國Ⅱ)

A. wear B. wears C. has worn D. have worn

分析：the only one of +名詞復數(shù)+who+謂語單數(shù)。選B,。

三. 如何確定“介詞+which/whom定從”中的介詞呢,？

如何確定“介詞+which/whom定從”中的介詞呢？應該把“介詞+which/whom”還原到定語從句中,，以便選擇介詞,。具體講有兩種方法：根據(jù)先行詞選擇介詞，根據(jù)從句動詞選擇介詞,。

①根據(jù)先行詞確定介詞,，即，介詞+名詞,，構(gòu)成介詞短語,。如，

●This is the city in which I lived.（I lived in the city→I lived in which→in which I lived）

●The pen with which she wrote the letter is lost.（she wrote the letter with the pen→she wrote the letter with which→with which she wrote the letter）

注意：“復合介詞+which”引導的定語從句,，常用倒裝語序,。（此時從句與主句之間用逗號隔開）。如,，The old man lived in a small house, in front of which stood a tall tree.（可參看第十二章“倒裝”）

②根據(jù)動詞確定介詞,，即，動詞+介詞,，構(gòu)成動介短語,。如，

●In the dark street, there wasn’t a person to whom she could turn for help.

在黑暗的街道上,，她沒有一個可以求助的人,。（turn to a single person→turn to whom）

●The woman about whom I talked at the meeting comes from Beijing.

我在會議上談到的那位女士來自北京。（talk about the woman→talk about whom）

注意：動介短語的固定搭配，介詞不能提到句首,，只能待在原地,。如，

This is the pen which/that I’m looking for.（√）,。This is the pen for which I’m looking.（×）

分組對比練習

題組17（根據(jù)先行詞確定介詞）

第1—6題考查“如何根據(jù)先行詞選擇介詞”,，第7—8題考查“定語從句中的倒裝語序”。

1. We went through a period _____ communications were very difficult in the rural areas.(2008,上海)

A．which B．whose C．in which D．with which 分析：in a period→in which,。選C,。

2. 100℃ is the temperature _____ which water will boil.(2012,全國Ⅱ)

A. for B. at C. on D. of

句意：100度是水沸騰的溫度。分析：at the temperature→at which,。選B,。

3. The schools themselves admit that not all children will be successful in the jobs ______they are being trained.（2005,江西） A. in that B. for that C. in which D. for which

分析：be trained for the job→be trained for which。選D,。

4.She showed the visitors around the museum,，the construction ____ had taken more than three years.(2011,江西) A．for which B．with which C．of which D．to which

分析：the construction of the museum→the construction of which。選C,。

5. Human facial expressions differ from those of animals in the degree _____ they can be controlled on purpose.（2007,重慶） A. with which B. to which C. of which D. for which

分析：to the degree→to which,。選B。

6. For many cities in the world, there is no room to spread out further, _____ New York is an example (2008,四川) A. for which B. in which C. of which D. from which

分析：an example of the cities→of which,。此題可以用來說明of which 從句也可以被分隔,。選C。

7. By nine o'clock, all the Olympic torch bearers had reached the top of Mount Qomolangma, _____ appeared a rare rainbow soon. (2008,福建) A. that B. which C. from which D. above which

分析：定語從句中用了倒裝語序,。選D,。

8. The factory was built in a secret place, around _____ high mountains. (陷阱題)

A. which was B. it was C. which were D. them were

分析：容易誤選A或B。其實,，定語從句中用了倒裝語序,。high mountains were around the factory→around which were high mountains。選C,。

題組18（根據(jù)從句動詞確定介詞）

1. Wind power is an ancient source of energywe may return in the near future. (2010,上海)

A. on which B. by which C. to which D. from which

句意：風力是一種古老的能源,，也許在不久的將來我們會再次依靠它。

分析：we may return to wind power→we may return to which→to which we may return,。選C。

2. We saw several natives advancing towards our party, and one of them came up to us, ____ we gave some bells and glasses.（2006,湖南）

A. to which B. to whom C. with whom D. with which

句意：我看到三個當?shù)厝讼蛭覀冏邅?，其中一個人來到我們面前,，我們給了他一些鈴鐺和眼鏡。

分析：we gave some bells and glasses to him→we gave some bells and glasses to whom,。選B,。

3. Gun control is a subject _____ Americans have argued for a long time.（2009,陜西）

A.of which B. with which C. about which D.into which

分析：不選B，因為，argue with sb.about/over sth.與某人爭辯某事,。選C,。

4. I saw a woman running toward me in the dark. Before I could recognize who she was, she had run back in the direction ______ she had come.(2006,重慶)

A．of which B．by where C．in which D．from which

分析：she had come from the direction→she had come from which→from which she had come。選D,。

四. whose與of whom/which引導定語從句的對比

whose與of whom/which的用法,，見下表，

1.一般地,，whose+名詞=the+名詞+of whom/which,。如，

I bought a bicycle. The bicycle’s handles were red.（兩個單句）→

I bought a bicycle whose handles were red.（“whose+名詞”引導定從）

I bought a bicycle. The handles of the bicycle were red.（兩個單句）→

I bought a bicycle the handles of which were red.（“the+名詞+of which”引導定從）

注意,，只有當作主語時,，“the+名詞+of which” =“of which the+名詞”。如,，

I bought a bicycle the handles of which were red.（the+名詞+of which）

=I bought a bicycle of which the handles were red.（of which+the+名詞）

=I bought a bicycle whose handles were red.（whose+名詞）

2.不定代詞/數(shù)詞+of whom/which,，只用在非限制性定語從句中，且此時的“of whom/which”不能用whose代替,。（這里的不定代詞有some, any, all, both, many, most等,。數(shù)詞有one, the first等。）（這里的“不能用whose代替”是很容易理解的,，因為,，顯然沒有“whose+不定代詞或數(shù)詞”這種結(jié)構(gòu)。）

●It’s a family of eight children, some of whom are studying music.

●Here are the questions, some of which I think difficult.

（I think some of which difficult→some of which I think difficult）

●Here are many books, two of which he borrowed.

（I borrowed two of which→two of which I borrowed）

分組對比練習

題組19（whose引導定語從句）

1. The school shop,customers are mainly students, is closed for the holidays. (2011,四川) A．which B．whose C．when D．where

句意：這個學校商店—其主顧大多是學生,，放假就關(guān)門了,。

分析：whose可以指物。選B,。

2. Children who are not active or diet is high in fat will gain weight quickly. (2010,北京)

A. what B. whose C. which D. that

句意：不愛運動或者飲食熱量偏高的孩子們會很快發(fā)胖,。

分析：children+ who…or whose…，兩個定語從句,。whose可以指人,。選B。

3. Look out! Don't get too close to the house____ roof is under repair.(福建高考題)

A. whose B. which C. of which D. that

句意：注意,！不要離正在維修屋頂?shù)哪菞澐孔犹?。分析：whose roof=the roof of which（這個結(jié)構(gòu)在作主語/賓語/表語時都成立）= of which the roof（這個結(jié)構(gòu)只有在作主語時成立）。選A,。

題組20（…of which/whom引導定語從句）

1. The man pulled out a gold watch, ____ were covered with some small diamonds.（2008,陜西）

A. the hands of whom B. whom the hands of C. which the hands of D. the hands of which

句意：那人拽出來一塊金表,，表的指針是用小鉆石做成的。分析：the hands of which=whose hands,。選D,。

2. Julie was good at German, French and Russian, all of ____ she spoke fluently.（2011,湖南）

A. who B. whom C. which D. that 分析：all of which,。選C。

3. I was given three books on cooking, the first ____I really enjoyed.(2006.浙江)

A.of that B.of which C.that D.which 分析：the first of which,。選B,。

4. I have many friends, ____some are businessmen.（全國卷）

A. of them B. from which C. who of D. of whom

分析：作主語時，some of whom= of whom some,。選D,。

5. In our class there are 46 students, _____ half wear glasses.(2012,四川)

A. in whom B. in them C. of whom D. of them

分析：作主語時，half of whom=of whom half,。選C,。

五.當先行詞是“時間/地點/原因/方式”時，如何確定引導詞,？

當先行詞是“時間/地點/原因/方式”時,，它的引導詞有三種情況：①代詞which/that，在定語從句中作主語/賓語/表語,。②副詞when/where/why,，在定語從句中作狀語。③介詞+which,，在定語從句中作狀語,。具體采用哪種引導詞，得看引導詞在從句所作成分,。

根據(jù)第四節(jié)第一小節(jié)的“定語從句的先行詞與引導詞總表”,，截取出下表：

下邊詳細講解此表。

1.先行詞是“時間/地點/原因等”時,，如果引導詞在從句中作名詞性成分（主語/賓語/表語）時,，則用which（代詞）；如果引導詞在從句中作副詞性成分（狀語）時,，則用when/where/why（副詞）,。

如何判斷引導詞在定語從句中作賓語還是狀語呢？當從句中的及物動詞或介詞后邊沒有賓語,，則,，引導詞應該用代詞。當從句中不缺主要成分（主語/賓語/表語）,，則,，引導詞應該用副詞。（因為副詞作狀語是次要成分）

例句（先行詞是時間）

I remember the day when we spent the holiday in the woods.（引導詞作狀語,，用副詞）

I remember the day (which) we spent in the woods.（引導詞作賓語,，用代詞）

例句（先行詞是地點）

This is the house where he lived.（live是不及物動詞，不需要賓語）

This is the house which he visited.（visit是及物動詞,，需要賓語）

例句（先行詞是原因(the reason)）

I know the reason why he did it.（引導詞作狀語,，用副詞）

I know the reason which he explained at the meeting.（引導詞作賓語，用代詞）

例句（先行詞是方式(the way)）

The way which he explained was quite simple.（代詞）

他向我們解釋的那種方法很簡單,。（方法本身很簡單）

The way (how×)/in which he explained the sentence was quite simple.（副詞性引導詞）

他向我們解釋句子的那種方法很簡單,。（解釋過程很簡單）

（這組與前三組的唯一不同之處是：沒有相應副詞how。前三組也可以用“介詞+which”,。）

2.關(guān)系副詞可以替換為“介詞+which(代詞)”,。即，when/where/why(副詞)=介詞+which(代詞),。（注意：只有在定語從句中,，when/where/why可以替換為“介詞+which”，在名詞性從句和狀語從句中不能替換,。）

●I remember the day when /on which the heat wave started.

●This is the place where /in which we used to live.

●High taxation is the main reason why /for which governments fall.

3.當先行詞是抽象地點或模糊時間,，引導詞常用where/when。

①表示抽象地點的先行詞（如case, degree, point, stuation）后,，一般用where（作狀語）引導其定語從句,，偶爾也用which（作主語/賓語）引導其定語從句?？傊?，抽象地點后的引導詞，其實仍然是很規(guī)則的,，只不過大多數(shù)都屬于該用where的情況而已,。

例句（抽象地點后，一般用where,，偶爾也用which,。）

●I can think of many cases ____you know nothing. （填副詞where）

●I can think of many cases ____you know nothing about. （填代詞which/that/?）

②表示模糊時間的先行詞（如，occasion,，stay,，interval），經(jīng)常用when（作狀語）引導其定語從句,。如,，

●The occasion when he is misunderstood often happen.他被誤解的情況時常發(fā)生。

4.當先行詞是“表示時間/地點的介詞短語”時,，引導詞用“介詞+when/where”,。如，“from/to+where”和“since/by+when”,。（對比：當先行詞是“表示時間/地點的名詞”時,，引導詞常用“介詞+which”或when/where。）

●We last saw the man in 1999, since when we have never heard of him.

（since when=since in 1999）

●They stood near the north window, from where they could see the whole garden.

（from where=from near the north window）

這種結(jié)構(gòu)并非特殊情況,，回顧以前學過的特殊疑問句,，也有“介詞+when/where”的用法,。

●where are you?你在哪里？where are you from?你來自哪里,？

分組對比練習

題組21（用which還是when/where/why）

1．The exact year____Angela and her family spent together in China was 2008. （2014,安徽）

A. when B. where C. why D. which

句意：安吉拉和他的家人在中國生活的確切年份是2008年,。

分析：…spent the year→…spent which→which…spent。選D,。

2. That evening, ___ I will tell you more about later, I ended up working very late.(2012,大綱)

A. that B. which C. what D. when

分析：…about the evening→about which→which…about,，選B。

3. The days are gone _____ physical strength was all you needed to make a living. (2011,天津)

A．when B．that C．where D．which

句意：只靠體力掙錢的時代已經(jīng)過去了,。分析：分隔性定語從句,，引導詞在定語從句中作時間狀語，用when,。The days are gone when physical strength was….,。選A。

4. The Science Museum, _____ we visited during a recent trip to Britain, is one of London's tourist attractions. (江蘇高考題) A. which B. what C. that D. where

句意：在最近一次去英國的旅游中,，我們參觀了科技博物館,，它是倫敦的旅游景點之一。分析：缺賓語,，用which/that,。選A。

5. —Can you believe I had to pay 30 dollars for a haircut?—You should try the barber’s ____ I go. It’s only 15. (2010,天津) A. as B. which C. where D. that

句意：—你能相信我理發(fā)得花20美元嗎,？—你應該到我常去的那家理發(fā)店試試,，那兒只需要15美元。分析：①I go to the barber’s (shop)→I go where→where I go,。②注意,，go是不及物動詞，不能go which（代詞）,，只能go where（副詞）,。選C。

6. Do you still remember the chicken farm_____we visited three months ago?（北京高考題）

A．where B．when C．that D．what

句意：你還記得三個月前我們參觀過的養(yǎng)雞場嗎,？

分析：we visited the chicken farm→we visited which/that→which/that we visited,，選C。

題組22（用when/where還是“介詞+which”）

1. We live in an age _____ more information is available with greater ease than ever before. （2012,，浙江）

A．why B．when C．to whom D．on which

句意：我們生活在一個比以往都能輕松獲得更多信息的時代,。

分析：不選D，因為,，in/during an age→in/during which,。選B。

2. — Mum, what did your doctor say?— He advised me to live_____ the air is fresher.(2006,四川)

A．in where B．in which C．the place where D．where

分析：選where,。不選B,，因為,，where引導狀語從句時，不能替換為“介詞+which”,。

3. The place____the bridge is supposed to be build should be____the cross-river traffic is the heaviest.(2005.江蘇) A. which, where B. at which, which C. at which, where D. which, in which 選C,。

題組23（先行詞是抽象地點或模糊時間）

考查“先行詞是抽象地點”的題非常多，此處只選擇了3個以point為先行詞的題（第1—3題）,。第4—6題考查“先行詞是模糊時間”。

1. We're just trying to reach a point_____both sides will sit down together and talk.(2006,山東)

A. where B. that C. when D. which

分析：引導詞在從句中作狀語,，應該用副詞,。選A。

2. After graduation she reached a point in her career _____she needed to decide what to do.（2007,，江西）

A．that B．what C．which D．where

分析：分隔性定語從句,。point+…+where。②引導詞在從句中作狀語,，應該用副詞,。選D。

3. —Do you have anything to say for yourselves?—Yes, there is one point _____ we must insist on.(2006,江西) A．why B．where C．how D．/

分析：引導詞在從句中作賓語,，應該用代詞,。there is one point which/that/不填 we must insist on，選D,。

4. Between the two parts of the concert is an interval, ____ the audience can buy ice-cream.（2011,江西） A．when B．where C．that D．which

句意：音樂會的兩個半場中間有間歇,，此時觀眾可以去買冰淇淋。

分析：引導詞在從句中作時間狀語,，選A,。

5. She'll never forget her stay there ____ she found her son who had gone missing two years before.（2009，四川） A．that B．which C．where D．when stay+…+when ,。選D,。

6. Occasions are quite rare ____ I have the time to spend a day with my kids. (2008,山東)

A．who B．which C．why D．when

句意：我有時間和孩子們一起度過一天的機會很少。分析：occasions+…+when ,。選D,。

題組24（介詞+when/where）

1. The book was written in 1946, __ the education system has witnessed great changes. (2007,山東)

A.when B.during which C. since then D. since when

句意：這本書寫于1946年，從那時起,，教育系統(tǒng)見證了巨大的變化,。分析：①不選since then，因為,，兩句中間有逗號,，所以，前后兩句是主從復合句,，后句是從句,，從句要用引導詞開頭,。②since when=since in 1946，選D,。

2. I have no idea ____ the journalist could have got his information from. （2011,上海春）

A. that B. why C. when D. where 分析：where…from=from where,，選D。

3. Jane is back in May, by____ the new house should be finished.（2008,非延考區(qū)）

A. which B. that C. whom D. when

句意：簡五月份回來,，屆時新房子應該完工,。分析：因為前邊有May，因此容易誤選A,。其實,，此時的先行詞應是前面的整個句子，強調(diào)的是“回來這一時間”,。選D,。

4.—____ when has the country been open to international trade? (2007,陜西)

—1978, I suppose. A. Since B. In C. From D. After

句意：這個國家從什么時候起進行國際貿(mào)易的？分析：since 意為“自從”,，常與現(xiàn)在完成時連用,，表示動作從某個時候開始，一直延續(xù)到現(xiàn)在,。選A,。

本文作者：高偉，編著《魔方英語語法》（高中版和教研版）,。

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