各位同學：

　　大家好!這一講我們一起來看一下語法在四級英語中的考查特點和應對策略。

　　英語是一個重結構的語言，要求句子必須符合句法結構的要求。用來規(guī)定句法結構的一些原則也就是我們常說的語法。英語中的語法條文比較多，總的來說可分為兩大類，即詞法和句法。具體說來，有情態(tài)動詞的用法，形容詞和副詞的比較級用法，非謂語動詞的用法，時態(tài)和語態(tài)，定語從句，狀語從句，虛擬語氣，名詞性從句，倒裝，強調與并列，主謂一致等。經(jīng)過統(tǒng)計，95年1月到2000年6月，僅詞匯和句法部分對語法的考查就有190題，占52.8%，其中以非謂語動詞、虛擬語氣、時態(tài)/語態(tài)、狀語從句和定語從句考查最多。今天這一講我們重點講時態(tài)/語態(tài)、虛擬語氣和各種從句，下一講重點講非謂語動詞等。

一、時態(tài)和語態(tài)

　　英語中共有16個時態(tài)，最常用的是一般現(xiàn)在時、一般過去時、一般將來時、現(xiàn)在和過去進行時、現(xiàn)在完成時、過去完成時。但從95年以來的考題統(tǒng)計來看，15個時態(tài)考題中將來完成最多，占3題，時態(tài)考查的次序依次為將來完成時--- 過去完成時 --- 現(xiàn)在完成進行時 --- 現(xiàn)在完成時 --- 一般將來 --- 一般過去。先看以下各題：

Test Yourself:
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1) My train arrives in New York at eight o'clock tonight. The plane I would like to take from there ___ by then.(1999.1)
A. would leave 　　B. will have left 　　C. has left 　　D. had left

2) She ought to stop work; she has a headache because she ____ too long.(2000.1)
A. has been reading 　　B. had read 　　C. is reading 　　D. read

3) "May I speak to your manager Mr. Williams at five o'clock tonight?"(2000.6)
"I'm sorry. Mr. Williams ____ to a conference long before then."
A. will have gone 　　B. had gone 　　C. would have gone 　　D. has gone

4) Great as Newton was, many of his ideas _____today and are being modified by the work of scientists of our time.(1997.1)
A. are to challenge 　　B. may be challenged 　　C. have been challenged 　　D. are challenged

5) Before the first non-stop flight made in 1949, it ____ necessary for all planes to land for refueling. (1996.6)
A. would be 　　B. has been 　　C. had been 　　D. would have been

6) He came back late, ____ which time all the guest had already left.(1999.6)
A. after 　　B. by 　　C. at 　　D. during

7) Until then, his family ______from him for six months. (1997.1)
A. didn't hear 　　B. hasn't been hearing 　　C. hasn't heard 　　D. hadn't heard

Explanation and Expansion
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A：參考答案：1）B 2）A 3）A 4）C 5）C 6）B 7）D
B：評析：

1) 以上各題都與完成時有關，完成時態(tài)用來表示到某一個時間為止已經(jīng)完成的動作或某個狀態(tài)/動作一直持續(xù)到某個時間。如果時間為過去，則用過去完成時，即表示過去的過去，如5）和7）。

2) 如果表示到將來某個時間為止已經(jīng)完成的動作，則用將來完成時，如1）和3），再如：
It's reported that by the end of the month the output of cement in the factory ____ about 10%.
A. will have risen B. has risen
C. will be rising D. has been rising

3) 而現(xiàn)在完成時表示到目前為止某個動作已經(jīng)結束，對現(xiàn)在有影響，如4）。從下文中的"正在修改"可以判斷人們已經(jīng)對牛頓的觀點提出挑戰(zhàn)，而不是將要提出挑戰(zhàn)或者可能提出挑戰(zhàn)，由此可以判斷應該用現(xiàn)在完成時。

4) 與現(xiàn)在完成時不同，現(xiàn)在完成進行時則表示某個動作從過去持續(xù)到現(xiàn)在，并且仍在進行，如2）。頭疼的原因是看書時間太長。本題可以用現(xiàn)在完成時，但不會是過去完成時，選項B不對，一般現(xiàn)在時表示經(jīng)常發(fā)生的動作，與這里的頭疼不能構成直接的因果關系，由于時間狀語表示的是一段時間，有不可能是現(xiàn)在進行時，所以這里只能用現(xiàn)在完成進行時。

C．完成時態(tài)使用注意事項
① 完成時的時間狀語一般表示"到……為止"，以"by"短語居多。如果句中的時間狀語是由by引出的短語或從句，謂語動詞一般是用完成時態(tài)，如：
By the time we got there, the fire had already been put out.
We'll have completed the task by the time you come back.

② 在完成時態(tài)中，終止性動詞不能與表示一段時間的時間狀語連用，而表示狀態(tài)或動作持續(xù)的謂語動詞必須與表示一段時間的狀語連用。
The conference ____ a full week by the time it ends
A. must have lasted
B. will have lasted
C. would last
D. has lasted (1997.1)
It seems oil ___ form this pipe for some time. We'll have to take the machine apart to put it right.
A. had leaked
B. is leaking
C. leaked
D. has been leaking (1997.6)
這兩題中都有表示動作持續(xù)的一段時間，應該用完成時態(tài)。
但是，如果只表示狀態(tài)已經(jīng)存在，則不能用完成時態(tài)，如：
By then, he knew what he waned to be when he grew up.

③ 完成時可以用來表示量的積累。

④ 對于完成時的考查有兩種，一種是時態(tài)本身的選擇，另一種是根據(jù)時態(tài)選擇時間狀語，如6）。從句時態(tài)為過去完成時，表示等到他回來，客人都已經(jīng)離開了，與完成時態(tài)連用的，表示"到……為止"的應該是介詞by。

Pactise Yourself
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　　下面請同學們做《語法分冊》第五章 二至四節(jié)相關題目。然后對照評析自檢。

Test Yourself
剛才我們看了完成時態(tài)的考查，現(xiàn)在我們一塊來看以下其它時態(tài)，請先試做以下各題：
1) Turn on the television or open a magazine and you _____ advertisements showing happy, balanced families.
A. are often seeing 　　B. often see 　　C. will often see 　　D. have often seen (1995.6)

2) While people may refer to television for up-to-the-minute news, it is unlikely that television _____ the newspaper completely.
A. replaced 　　B. have replaced 　　C. replace 　　D. will replace (1995.6)

3) I'm sorry I can't see you immediately; but if you'd like to take a seat, I'll be with you ____.
A. for a moment 　　B. in a moment 　　C. for the moment 　　D. at the moment (1999.1)

4) If she doesn't tell him the truth now, he'll simply keep on asking her until she _____.
A. does 　　B. has done 　　C. will do 　　D. would do (1998.6)

Explanation and Expansion
A. 參考答案： 1）C 2） D 3） B 4） A
B. 評析
　　從以上各題可以看到，在解時態(tài)考題時應注意一下幾點：
① 結合形容詞選擇時態(tài)，如2）。從unlikely一詞可以看出從句表示的是將來不大可能發(fā)生的事情，自然用一般將來時。類似的形容詞還有possible, probable, impossible等。

② 根據(jù)時態(tài)判斷時間狀語。如3）。謂語動詞為將來時態(tài)，說明時間應該是in a moment，表示我一會就去見你。for a moment同樣可以與將來時態(tài)連用，但表示的是"與某人一塊待一小會"，這樣就與上文的I can't see you immediately意思上沖突。

③ 注意句型對時態(tài)的要求，如1）。該句型中祈使句表示一種條件，第二個分句中一般要用will表示在這種條件下可能發(fā)生的事情。但是，本題中often的使用可能會造成一定的迷惑。這就要求考生對各種時態(tài)的表達方式，以及其作用了解清楚。Will可以表示習慣。

④ 注意時間、條件和讓步狀語從句中時態(tài)的運用。

　　一般在時間、條件和讓步狀語從句中用一般現(xiàn)在時表示一般將來，用一般過去時表示過去將來，用現(xiàn)在完成時表示將來完成，用過去完成時表示過去將來完成。如4）。在如：
He promised to send me an email as soon as he got there.
No one is to leave the room until he has done the task.
但注意特殊句型中的時態(tài)，如：
hardly/scarcely …when…
no sooner… than…
Hardly had I put down the receiver when the telephone rang again.
No sooner had they got to know the news than they went to the bar to enjoy a drink.

Self-practice
請同學們做《語法分冊》第五章 第六節(jié)進行自我訓練。

Test Yourself
剛才我們一起分析了時態(tài)的考查特點和答題時應該注意的事項，現(xiàn)在我們一起來看一下語態(tài)的考查。語態(tài)的考查一般都與時態(tài)的考查相結合。在解語態(tài)題的同時必須考慮時態(tài)的因素。請同學們先做以下下列各題：
1) The last half of the nineteenth century ____ the steady improvement in the means of travel.(1998.6)
A. has witnessed 　　B. was witnessed 　　C. witnessed 　　D. is witnessed

2) The grey building is where the workers live, and the white one is where the spare parts ____.(19995.1)
A. are producing 　　B. are produced 　　C. produced 　　D. being produced

3) This kind of glasses manufactured by experienced craftsmen ____ comfortably.
A. is worn 　　B. wears 　　C. wearing 　　D. are worn (2000.1)

4) The fifth generation computers, with artificial intelligence, ____ and perfected now.(1996.1)
A. developed 　　B. have developed 　　C. are being developed 　　D. will have been developed

5) Sir Denis, who is 78, has made it that much of his collection ____ to the nation.(1996.6)
A. has left 　　B. is to leave 　　C. leaves 　　D. is to be left

6) As teachers we should concern ourselves with what is said, not what we think ____.(1997.6)
A. ought to be said 　　B. must say 　　C. have to be said 　　D. need to say

7) Once environment damage ____, it takes many years for the system to recover.(1997.6)
A. has done 　　B. is to do 　　C. does 　　D. is done

Explanation and Expansion
A. 參考答案：1）C 2） B 3） B 4） C 5） D 6） A 7）D
B. 評析
① 是否可用被動語態(tài)主要看謂語動詞與句子主語之間的關系，如果是動賓關系自然用被動語態(tài)。

② 注意被動語態(tài)的各種時態(tài)構成，但四級考試中沒有正誤結構的判斷，考生只需要根據(jù)上下文判斷出該用什么時態(tài)即可。

③ 不及物動詞不可能有被動語態(tài)，但及物動詞也未必有被動語態(tài)，主要是看句子側重表達的概念，如3題中wear表示眼鏡的特點，不可用被動語態(tài)。在如：
This kind of software sells well.
It being too cold, the car wouldn't start.
won't wouldn't表示"拒絕"謂語動詞不用被動形式。

④ 注意含有情態(tài)動詞的被動語態(tài)的結構，以及類似的結構，如have to be done, used to be done, be said to be done, be to be done。把握各種結構表示的意思。然后就是根據(jù)具體的上下文選擇適當?shù)那閼B(tài)動詞或時態(tài)的問題。
Self-practice

　　好，剛才我們一起了解了被動語態(tài)的考查特點和解題注意事項，下面請同學們請做《語法分冊》第六章 第四節(jié) 自我訓練題。

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