（浙江省淳安中學 邵一平）
(1) 語法講解：同步教材重難點語法講解
1. 不同時態的問句形式（Revision of question forms in different tenses）
疑問句就是提出問題的句子。有四種：a. 一般疑問句（General Questions）； b. 特殊疑問句（Wh-Questions）；c. 選擇疑問句（Alternative Questions）； d. 反意疑問句（Tag-Questions）。
可用于各種時態。 如：
Who is that boy over there?
What do you know about Bob White ?
Which school did he go to last year?
Which school does he go to now?
Which subject is he going to study this term?
What was he doing at this time last week?
How many Chinese words has he learnt?
2.直接引語和間接引語 (Direct and indirect speech)
當說話人引用別人的話時，可以用別人的原話，也可以用自己的話把別人意思轉述出來，引用原話，稱為直接引語（Direct Speech），否則稱為間接引語（Indirect Speech）。直接引語通常用引號（“”）括起來，間接引語在多數情況下都構成一個賓語從句。
1. 如果引用的句子原來是一個陳述句，在間接引語中要注意下面幾點：
（1）在引語的開頭用連詞that，有時可以省略
He said: “mother, the boy is very naughty.”
He told his mother that the boy was very naughty.
（2）根據意思改變人稱
She said: “your pronunciation is better than mine.”
She said that my pronunciation was better than hers.
（3）注意間接引語中的謂語與句子主要謂語時態一致
“Frank, I came to return you the book,” Henry said.
Henry told Frank that he had come to return the book.
（4）根據意思將指示代詞，地點及時間狀語作必要的更動
She said: “I will come here again tonight.”
She said she would go there again that night.
2. 直接引語是一個疑問句變間接引語時，除了注意人稱、狀語等的變更和時態一致之外，還要注意：
（1）把疑問句語序變為陳述句語序，也就是說要把主語放在謂語的前面。
He asked: “ How are you getting along?”
He asked us how we were getting along?
（2）在這種引語前“that”是永遠也不能用的。如果是一個一般疑問句、選擇疑問句或反意問句，在引語前要用連詞whether或if。
He asked: “Are you a Party member or a League member?”
He asked me whether I was a party member or a League member.
（whether…or…搭配，一般不用if）
“You’ve already got well , haven’t you ?” she asked.
She asked whether（if）he had already got well .
3. 現在進行時表示將來動作（the present continuous tense-future use;）
現在進行時是由助動詞am，is或are加行為動詞的現在分詞構成。 基本用法是表示說話時正在進行的動作,可與now, at present, right now等時間狀語連用, 現在進行時與always, often, all the time等連用可表示反復性、一貫性的動作,且常帶有贊揚或厭惡的感情色彩。除了表示現階段正在進行的動作和表示一貫性的動作之外，還表示即將發生的動作。
考點說明: come, go, leave, arrive, start, fly, drive等動詞可用現在進行時表示一個按計劃或安排好將要發生的動作即將發生的動作。
典型例題1:I want to know when he _____ for New York.
A. has left B. is leaving C. had left D. would leave
解析:由句意“我想知道他什么時候動身去紐約”可知此處表示將來, D項為過去將來時,與主句時態不一致。故答案選B。
典型例題2: Ladies and gentlemen, please fasten your seat belts. The plane_______. (06福建卷24).
A. takes off B. is taking off C. has taken off D. took off
解析: 這里用現在進行時表示將來的動作。是口頭通知的常用語，“女士們，先生們，清系好安全帶，飛機就要起飛了。” 故答案為B。
典型例題:
1.“Where does your chemistry teacher live, Karen?” the young man asked.
The young man asked Karen where her chemistry teacher lived.
簡析:一般說來,直接引語是疑問句,將其變為間接引語時,原來的疑問語序要改為陳述語序。
2.“I have gained the first place in the mathematics competition,” the little boy said happily.
The little boy said happily that he had gained the first place in the mathematics competition.
簡析:直接引語變為間接引語時,若主句的謂語動詞是一般過去時,從句的謂語動詞一般要用相應的某種過去時態, 所以本句中的現在完成時應改為過去完成時。
3.“Light travels faster than sound,” the physics teacher said to the boys and girls.
The physics teacher told the boys and girls that light travels faster than sound.
簡析:直接引語為客觀真理、格言時,變為間接引語,時態無需改變。
4.“Will you go to the concert with me this evening?” Mary asked me.
Mary asked me if / whether I would go to the concert with her that evening.
簡析:直接引語如果是一般疑問句,變為間接引語時,要用連詞whether或if引導,而不用that。
5.“What did you do here yesterday?” the old man asked my brother.
The old man asked my brother what he had done there the day before.
簡析:直接引語變為間接引語時, 指示代詞、時間狀語、地點狀語一般也要作相應改變,如
this, these, here, now, today, tomorrow, yesterday等分別改為that, those, there, then, that day, the next day, the day before等。
6.“Speak English more often in and out of class,” our English teacher said to us.
Our English teacher told /asked us to speak English more often in and out of class.
Our English teacher suggested that we (should)speak English more often in and out of class.
簡析:直接引語是祈使句,變為間接引語時,要將祈使句的動詞原形變為帶to的不定式,并在不定式的前面根據語氣需要使用ask, tell, order等動詞,其句型是:ask/tell/order someone to do sth.,但是suggest不能接不定式作賓補,只能接-ing形式或從句(從句用虛擬語氣)作賓語。
7.“Don’t play football on the street, little boys,” the policeman said.
The policeman told the little boys not to play football on the street.
簡析:如果直接引語是祈使句的否定式,變為間接引語時,要將其改為不定式的否定形式作賓補,不定式的否定形式是在不定式前面加not,而不是加do not, does not, did not等。
8.“Would you please do me the favor to carry the box upstairs?” the young woman said to me.
The young woman asked me to carry the box upstairs for her.
簡析:直接引語是一些表示請求、建議的疑問句,變為間接引語時, 也變為不定式作賓語補足語。需要注意的是應根據原句的語氣選用恰當的動詞。因為此處原來的疑問句用的是很客氣的語氣,改寫后不宜用order。
9.“You clean the classroom after class today, Tom,” said the monitor.
The monitor told Tom to clean the classroom after class that day.
簡析:一般而言,祈使句是以動詞原形開頭的,但是如果說話人有意強調動作執行者,也可以在句首加上主語。我們在將其變為間接引語時不能將帶有主語的祈使句與陳述句混淆起來。
10.“It’s a fine day. Let’s go to the country for a picnic,” Peter said to me.
Peter said that it was a fine day and asked me to go to the country for a picnic with him.
簡析:當直接引語中有多種句子形式如陳述句、祈使句、疑問句等時,我們就要用不同的方式將各種句子進行轉述。因為原句中直接引語前面部分是陳述句,故變為由that引導的賓語從句,后面部分是祈使句所以變為不定式作賓補。
(2)相關高考試題詮釋
[經典句1]：1) I don’t enjoy singing, nor do I like computers.
2) Rock music is OK, and so is skiing. (Unit1, Speaking)
[考點透視]
句1)是“neither/nor+系動詞/助動詞/情態動詞+主語+動詞”的倒裝結構,表示兩個句子主語一致,但否定不同的內容;若兩個句子主語不同,但否定相同的內容,則用“neither/nor+系動詞/助動詞/情態動詞+主語”結構。
句2)是“so +系動詞/助動詞/情態動詞+主語”結構,表上句的情況也同樣適用于后者,其主語與上句的主語不同;而 “so +主語+系動詞/助動詞/情態動詞”結構表示上句提到的情形的確如此,對其進一步強調,兩句的主語相同。
[高考題1]---Do you know Jim quarreled with his brother?
---I don’t know, _______. (MET 1991)
A. nor don’t I care B. nor do I care
C. I don’t care neither D. I don’t care also
[詮釋] 這里是“neither/nor+系動詞/助動詞/情態動詞+主語+動詞”的句型。答案為 B.
[高考題2] --- David has made great progress recently.
--- _______, and _______.(上海1997)
A. So he has; so you have B. So he has; so have you
C. So has he; so have you D. So has he; so you have
[詮釋] 這是肯定語氣中的句型“so +系動詞/助動詞/情態動詞+主語”結構，答案為 B.
[高考題3]---It’s burning hot today, isn’t it?
---Yes. ________yesterday（06福建卷）
A. So was it B. So it was C. So it is D. So is it
[詮釋] 這里是句型“so +系動詞/助動詞/情態動詞+主語”結構，表示“昨天與今天一樣都天氣熱”，故答案為 A.
[經典句2]：One day Chuck is on a flight across the Pacific Ocean when suddenly his plane crashes. (Unit1, Reading)
[考點透視] 連詞when引起時間狀語從句時,通常意為“當……時候”。此處的when相當于and then, and just at that time,可意為“就在那時,突然”。主句多用過去進行時或be about to 結構,when 引起的從句則多用一般過去時。
[高考題1] We were swimming in the lake ____ suddenly the storm started. (04北京春)
A. when B. while C. until D. before
[詮釋] 此處的when意為“就在那時,突然”。與后面的“suddenly”呼應，故答案為 A.
[高考題2] He was about halfway through his meal a familiar voice came to his ears.（06遼寧卷）
A. why B. where C. when D. while
[詮釋] 主句用了be about to 結構,意思是“正準備做…”,與when 引起的從句連用。故答案為 C.
[高考題3].I along the street looking for a place to park when the accident __ ．(2006安徽高考)
A．went; was occurring B. went; occurred
C．was going; occurred D．was going; had occurred
[詮釋] 這里的主句要用過去進行時,因從句中有when 引起的從句，而且從句多用一般過去時。答案為 C.
[經典句3]：Chuck learns that we need friends to share happiness and sorrow. (Unit1, Reading)
[考點透視] share作動詞,表示“分享,共同使用;共同具有,有同樣的……”,share out表示“分給(一些人)”;share with表示“與……合用”。
[高考題] Let Harry play with your toys as well, Clare? you must learn to _____. (NMET 2000)
A. support B. care C. spare D. share
[詮釋] 這里考查 “share with sb. sth.”結構，答案為D.
[經典句4]： ..., it will become more and more important to have a good knowledge of English.( Unit 2, Reading)
[考點透視] knowledge通常為不可數名詞,但表“對…懂, 對…有某種程度的了解”時,通常前面可加不定冠詞。
[高考題1] .They have a good knowledge of English but little ____ they know about German. （05 天津高考卷）
A. have B. did C. had D. do
[詮釋] 這里“have a good knowledge of English” ,意思為“對英語有某種程度的了解”，與后面的 “know”意思相同。答案為D.
[經典句5]：For a long time the language in America stayed the same, while the language in England changed. (Unit 2, Integrating Skills)
[考點透視1] stay在句中是連系動詞,也就是說stayed the same是系表結構,所以此時stay不可以用于進行時態和被動語態。
[高考題] Why don’t you put the meat in the fridge? It will ______ fresh for several days. (NMET 2003)
A. be stayed B. stay C. be staying D. have stayed
[詮釋] stay fresh是系表結構, 故stay是連系動詞，答案是B.
[考點透視2] 連詞while在句中的意思是“但是、然而”,表示轉折或對比關系。
[高考題1] She thought I was talking about her daughter, ______, in fact, I was talking about my daughter.(NMET 1995)
A. whom B. where C. which D. while
[詮釋] 這里考查while連詞。在句中的意思是“但是、然而”,表示轉折或對比關系。所以選D.
[高考題2] We thought there were 35 students in the dining hall, ____, in fact, there were 40. (06全國卷II, 13)
A. while B. whether C. what D. which
[詮釋] 此處while在句中的意思是“但是、然而”, 表示轉折或對比關系。答案 A.
[高考題3] The cost of living in Glasgow is among the lowest in Britain, the quality of life is probably one of the highest. (06天津卷,).
A. since B. when C. as D. while
[詮釋] 此處while表示對比關系，“然而”，答案 D.
[經典句6]： That’s why the words color, centre and traveler are spelt color, center and traveler in American English.( Unit 2, Integrating Skills)
[考點透視]why的意思是“為什么、……的理由”,在句中是連接副詞,引導表語從句,從句的內容表示結果。
[高考題] You are saying that everyone should be equal, and this is _______I disagree.(NMET2004 31)
A. why B. where C. what D. how
[詮釋] 檢查考生對名詞性從句的掌握和運用能力。意思為“你說人人應該平等，在這一點上我不敢茍同。”where 在表語從句里充當狀語，有“在…地方”的含義。B最佳。
[經典句7]： However, most of the time people from the two countries do not have any difficulty in understanding each other. (Unit 2, Integrating Skills)
[考點透視] 表示“做某事有(無)困難”可用句型have (no)difficulty (in)doing sth.,其中的difficulty是不可數名詞,也可以用trouble,句型中的介詞in可省掉;如表示“在某方面有(無)困難”,則用have (no) difficulty with sth.
[高考題] .There ____ be any difficulty about passing the road test since you have practised a lot in the driving school. （2005 上海卷）
A. mustn’t B. shan’t C. shouldn’t D. needn’t
[詮釋] 這里是考句型, “there be no difficulty about (in) doing sth. =have (no) trouble in doing sth”, 表示“做某事有困難”, difficulty 和trouble 都是抽象名詞，故答案為C.
[經典句8]：...or simply to get away from cold weather. ( Unit3, Reading)
[考點透視] get away from除表示 “逃離”外, 還可意為 “走開, 離開;拿走,(使)離開”。
[高考題] His mother had thought it would be good for his character to _____ from home and earn some money on his own. (北京2002)
A. run away B. take away C. keep away D. get away
[詮釋] 這里考詞組短語的區別。run away from從……逃跑;掙脫……;take away from 從……拿走;keep away from “(使)不靠近”。根據題意,應選D。get away from意為 “走開,離開;”
[經典句9]：You should not go rafting unless you know how to swim, and you should always wear a life jacket. ( Unit3, Reading)
[考點透視] 連詞unless的意思是“除非、如果不”,常可以與if...not互換。引導條件狀語從句時,從句的謂語動詞經常用一般現在時表將來。
[高考題1] The men will have to wait all day ______ the doctor works faster. (北京2001春)
A. if B. unless C. whether D. that
[詮釋] 這里連詞unless是“除非、如果不” 的意思，故選B.
[高考題2] You will succeed in the end ______ you give up halfway. (2001上海春)
A. even if B. as though C. as long as D. unless
[詮釋] 用unless引導假設關系, 對比“succeed”與“give up”兩者關系，意為 “除非你中途放棄，你會最終成功的。”
[高考題3]. ________ you have tried it, you can’t imagine how pleasant it is. (06北京卷，33)
A. Unless B. Because C. Although D. When
[詮釋] 這里unless意思是“如果不”,可以與if...not互換。答案: A
[考例4] We don’t keep winning games _______ we keep playing well. (06浙江卷，2)
A. because B. unless C. when D. while
[詮釋] 這里連詞unless是“除非”的意思。強調條件。答案: B
[經典句10]： By staying at hotels in Red River Village, tourists can help the villagers make money so that they can take care of the river and the birds. (Unit3, Integrating Skills)
[考點透視1] by用作介詞,表示“用……方式,憑借……手段”,后接動詞時用其-ing 形式。
[高考題1] One learns a language by making mistakes and _______ them. (北京2001春)
A. correct B. correcting C. corrects D. to correct
[詮釋] 由句意及連詞and可知,空缺處應與making mistakes并列作介詞by的賓語,故選B。
[考點透視2] so that通常用來引導目的狀語從句,意思是“為了……、以便于”,從句的謂語動詞通常與情態動詞連用。此外，so/ such a… that 還可表示結果。結果狀語從句中一般不與情態動詞連用。
[高考題2] Roses need special care _____ they can live through winter. (NMET 2004)
A. because B. so that C. even if D. as
[詮釋] 根據題意 “玫瑰需要特別的關照以便它們能夠越冬”,可知此處表示目的,故選B。
[高考題3].His plan was such a good one ______ we all agreed to accept it.（06陜西高考卷）
A. as B. that C. so D. after which
[詮釋] 這里such a… that 連接結果狀語從句。答案B.
(3)專項練習題: (30道)
1. Mary was about to go to bed ___________ someone knocked at the door.
A. when B. while C. as D. since
2.---Why are you so tired?
--- I have been cleaning the room _______ this morning.
A. all time B. all the time C. all times D. the all time
3、Because the climbers _____a heavy rain, they had to stop climbing the high mountain.
A. caught B. caught in
C. were caught D. were caught in
4. We ________ visiting the Great Wall next week.
A. thought B. wanted C. considered D. expected
5. He told me that he better .
A. was, that day B. is, today C. was, this day D. is, the day
6. I did wrong to him. Please ____sorry to him _____ me.
A. say; to B. say; for C. tell; for D. tell; to
7. Would you like _________ some coffee?
A. drink B. drinking C. to drink D. to drinking
8. I _______ back tomorrow unless it______
A. will; rains B. will be; rains
C. am; rains D. will be; is going to rain
9. He ________ a week in finishing the experiment.
A. took B. cost C. spent D. paid
10. Jane ______ have kept her word. I wonder why she changed her mind.
A. must B. should C. need D. would
11. It is said that the earth is becoming warmer and warmer, How does this ?
A. come from B. come back C. think about D. come back
12. They went on a travel on foot _________by bus.
A. instead B. take the place of
C. in the place of D. instead of
13. --- Take a short rest, will you?
--- Ok, I’m tired after a long walk.
A. more or less B. more and more
C. as a result D. for example
14. I know that gentleman like you ____ only large notes.
A. take B. fetch C. bring D. carry
15. You must do _______ I tell you.
A. that B. as C. like D. which
16. It didn't take long before the wooden building ______by the fire.
A. swallowed up B. was swallowing up
C. was swallowed up D. has swallowed up
17. Another wave _____the house, and a strange cracking noise began.
A. struck B. beat C. felt D. dragged
18. I ________ he will visit the United States with me.
A. am hoping B. hope C. have hoped D. am hoped
19. George _____the good chance to hand his suggestions to the director, and at last, it was accepted.
A. covered B. seized C. advance D. thought
20. I prefer coffee _____ milk. But they prefer _____ juice ______ soup.
A. to; to drink; drinking B. to; drinking; to drinking
C. at; drinking; to drinking D. at; to drink; to drink
21. We had to pay the rent two weeks in_______.
A. advance B. trouble C. ahead D. total
22. The slaves were fighting _____the slaver owners _____ their freedom.
A. for; with B. for; against C. with; against D. against; for
23. Paper __________ easily.
A. is catch fire B. catches fire
C. is caught fire D. is on fire
24. The old lady, _____ had been killed in the war, was given help by the local government.
A. all her children B. all of her children
C. all of whose children D. whose all children
25. When Lucy came back from work, she found her husband _____ in the kitchen and all the housework ____.
A. cooking; done B. cook; done
C. cooking; do D. cooking doing
26. The box is _______ what I saw in the shop.
A. same as B. the same like
C. the same that D. the same as
27. The name sounds like a stranger, _______ I think I have never heard.
A. whom B. of which C. to which D. which
28. You should make it a rule to leave things ______ you can find them again.
A. when B. where C. then D. there
29. The students ______ busily when Miss Brown went to get a book she _____ in the office.
A. had written; left B. were writing; has left
C. had written; had left D. were writing; had left
30. It ________last night, for the ground is wet.
A. must rain B. must have rained
C. must to rain D. must have rain
(4)專項練習題答案詳解:
1. 與主句be about to 結構聯系起來考慮,此處的when相當于and just at that time,意為“就在那時,突然”。答案為A.
2. 從謂語“have been cleaning”可知是現在完成進行時，所以是“all the time”，意思是“一直”，答案為B.
3. 表示“受困，受阻”意思的短語是“be caught in”. 這里要注意用被動結構， 還要不忘記接介詞in, 在雨中是“in the rain”. 所以答案是D.
4． 這里要看動詞與賓語的搭配，賓語是動名詞visiting 只有consider后直接跟動名詞。 Want 和 expect 要跟動詞不定式， think 要加介詞 of / about 再接動名詞。所以答案是C。
5. 考查間接引語的用法。 動詞told過去式時，后面跟的賓語從句也應時態一致。相應的時間狀語也要改變。所以答案是A.
6．考查短語搭配。 “say sth．to sb. for sb”意思是“替某人向某人說……”。所以答案是B.
7．would like后跟不定式，不跟動詞-ing形式。所以答案為C。
8．在條件狀語從句中，主句是將來時的，從句要用一般現在時代替一般將來時。這里是unless引導的條件狀語。所以選B。
9．考查近義詞的區別。都是“花費”之意。Take 主語通常是it; spend指花費時間和金錢，主語通常是人; cost主語通常是物； pay主語通常是人,但要注意搭配“pay sb. Sth. 或pay for sth.”。所以要選C.
10．這里考情態動詞的用法。 must have done“想必或一定已經做……”。Should have done “本應該做… 而沒做”.would have done“本來會做而沒做”，need have done“原來需要做…”. 所以從文中 “kept her word”與“changed her mind”，可推出答案是B.
11. 考查動詞短語的區別。come from “來自”；come back“返回” ; .think about “思考，考慮” ； come about“產生，帶來”。 根據句子意思，是“全球變暖是怎么產生的。”答案為D.
12．instead of介詞短語，表示“舍去”的動作，即不去做； instead 放句尾，表示“取”的動作，即去做某事；in the place of= take the place of 都表示“代替，替代”。 所以答案為D。
13. 此題考查副詞短語的不同意思和用法。這里副詞短語都做狀語，但意思不同：more and more“越來越多”；
as a result“結果是”；for example“舉例”；more or less “或多或少”，表示程度，所以選A.
14．這里考查動詞的近義詞的區別。都有“攜帶，拿，取”的意思。 Take “帶來”； bring“拿去”；fetch“去取回來”；都有方向性。“carry作“帶”講，沒有方向性。這里是“隨身攜帶”的意思。 所以答案是D.
15．as用作連接代詞，“按照，正如”的意思。引導賓語從句。 故選B。如果加個名詞/代詞作賓語（作先行詞），再跟個定語從句，那么就選A 或C了。Like 是介詞。故不對。
16. 這里考查動詞短語的被動式用法。句子意思“木屋被大火所吞沒”， 從時態語態上考慮，答案是C.
17. 這里是動詞近義詞的區別。Beat “鞭打，毒打”；feel “觸摸，感覺”；drag “拖，拽”； strike “敲打，沖擊”, 所以選A.
18．這里考查hope 動詞的用法，一般狀態動詞沒有進行時態。從后文的will 可知賓語是將來時，所以選一般現在時，答案B。
19． 這里與chance 的搭配只有seize, 表示“抓住機會”的意思，其他的動詞都沒有這樣的搭配，所以答案B.
20．這里考查prefer的兩個結構“prefer sth．to sth．和prefer doing．．to doing…的區別。句子為 “I prefer coffee to milk. But they prefer drinking juice to drinking soup.” 意思是“咖啡與牛奶我更喜歡咖啡，但他們喜歡喝果子汁勝過喝湯。” 所以答案選B。
21. 這里考介詞短語的含義區別, in trouble “陷入困境”; in total “總共,總計”; in advance “事先”; ahead “在前,超出”(不需加介詞). 從句子意思看, 應選A.
22.本題考查的是與fight搭配的介詞的用法，“為……而和某人作斗爭”應為fight against/with sb. for sth.。 答案：D
23.本題考查的是詞組catch fire 和on fire的用法及區別。我們可以看出出題人想表達的句意思為“紙張很容易著火”，強調的應該是“著火”的瞬間動作，而不是“(火）正在燒”的狀態，故要選擇catch fire，而A選項結構錯的，C的語態不對，不應用被動態。答案：B
24. 本題考查的是定語從句的關系代詞的選擇，首先從句子的結構可以看出“___ had been killed in the war”是“the old lady”的定語從句，先排除A和B項，而D項的語序顯然是錯的，應為all whose children。答案：C
25.本題考查的是find和一些感官動詞后的復合賓語的各種形式。首先判斷句意為“露西下班回到家時，發現她的丈夫正在廚房做飯而且所有的家務都已經被做完了。”所以，我們可以先排除C和D項，因為第二空之前的賓語“all the housework”和賓語補足語動詞“do”之間是被動關系，應用過去分詞表示被動，而第一空之前的賓語“her husband”和其賓語補足語動詞“cook”之間是主動關系，并強調“cook”這一動作在“露西下班回到家時”正在進行，故用現在分詞來表示。答案：A
26.形容詞same之前，一般要有定冠詞the，而且same 應與as連用。答案：D
27. 本句是一個含有介詞加關系代詞引導的定語從句的復合句。作“聽說”講時，應用hear of sth. / sb.，故關系代詞which之前應用of。答案：B
28．本題考查的是地點狀語從句。這句話的意思是“你應給讓把東西放在能夠再找到的地方成為一條規矩。where在該句中作連詞，該地點狀語從句相當于“in the place where you can find them again”的關系副詞where引導的定語從句。答案：B
29.從busily一詞和when引導的時間狀語從句可知，“學生們正在忙于寫字”，又因為“把書忘在辦公室”這件事發生在“拿書之前”，所以要用過去完成時，這句話的意思是：“當布朗小姐去辦公室拿她忘在那兒的書時，學生們正在忙于寫字。”答案：D
30. 這里是考查情態動詞的猜測語氣用法，這里的時間是last night,對過去的猜測用“must have Vpp”, 后面for 引導的句子是根據，“因地上是濕的”。答案為B.