高中語法專練：i. 主語從句

i. 主語從句

1. that從句作主語通常用it作形式主語，常見的這樣的主語從句結(jié)構(gòu)有：

1）It + be +名詞（a pity/fact/problem/shame/surprise/no wonder等）+that從句

It is a pity that we missed the interesting film.

很遺憾我們錯過了那場有趣的電影。

It is an honor that I am often invited to dinner.

真榮幸我經(jīng)常被邀請去赴宴。

2）It+be+形容詞（natural/certain/clear/obvious/evident/necessary/true/likely/probable/possible/strange/important等）+that從句

It is likely that it will snow this afternoon.

很有可能今天下午要下雪。

注意： 當形容詞是important/natural/necessary/strange/essential/surprising等時，從句謂語用（should）+動詞原形

It is necessary that we (should) buy a new car.

我們很有必要買輛車。

3）It+不及物動詞（seems/turns out/happens/appears/follows/occurs to sb.）+that從句

It seems that our sports meeting will have to be put off because of the weather.

我們的運動會似乎因天氣原因?qū)⒉坏貌槐煌七t。

It occurred to her that she had forgotten to lock the door.

她突然想起忘記鎖門了。

4）It+be+過去分詞（known/said/reported/believed/announced/accepted/found/claimed/declared/thought/hoped/suggested）+that從句

It is said that they have succeeded in passing the college entrance exam.

據(jù)說他們成功地通過了大學入學考試。

It has been proved that light runs much faster than sound.

已證實光速比聲速快得多。

注意： 當過去分詞是suggested/demanded/required/commanded/recommended/ordered等時，從句謂語用 (should) +動詞原形

It is required that every one (should) obey the traffic rules.

要求每一個人都應(yīng)該遵守交通規(guī)則。

注意：

1）在正式文體中，為了強調(diào)that從句，可將that從句置于句首。

That China is in the east of Asia is well known to all of us.

中國位于亞洲東部這是眾所周知的。

That the driver could not control his car was obvious.

很明顯司機不能控制他的車了。

2）在疑問句中只能用形式主語it結(jié)構(gòu)。

Is it true that he would take the risk?

他是真的要冒險嗎？

Isn't it amazing that so many passengers were unhurt in the accident?

那么多旅客在事故中沒有受傷難道不令人吃驚嗎？

2. wh-從句

1）表示“是否”意義時，只能用whether不能用if引導主語從句。

Whether a new product sells well depends on its quality and price.

一種新產(chǎn)品是否暢銷取決于它的質(zhì)量和價格。

2）it經(jīng)常用來作形式主語，而把wh-從句放句尾，常見的結(jié)構(gòu)為：

It is not yet clear wh- ....

It is strange wh- ....

It is uncertain wh- ....

It it not known wh- ....

It depends on ... wh- ....

It depends on its quality and price whether a new product sells well.

一種新產(chǎn)品是否暢銷取決于它的質(zhì)量和價格。

It isn't clear whether she would come.

她是否愿意來還不清楚。

3）wh-從句經(jīng)?？梢苑啪涫住?

What he said didn't refer to me.

他所說的并非指我。

Who should be chosen to do the job hasn't been decided.

誰應(yīng)該被選中做這件工作還沒決定。

What he needs is more experience.

他所需要的是更多的經(jīng)驗。

Where we will go for our holiday hasn't been decided.

我們?nèi)ツ膬憾燃龠€沒有決定。

專項練習

1. _______ she couldn't understand was _______ fewer students showed interest in her lessons.

A. What; why

B. That; what

C. What; because

D. Why; that

2. It worried her a bit _______ her hair was turning gray.

A. while

B. that

C. if

D. for

3. It is pretty well understood _______ controls the flow of carbon dioxide in and out the atmosphere today.

A. that

B. when

C. what

D. how

4. _______ man first made use of electricity is not exactly known.

A. When

B. If

C. That

D. What

5. _______ we will have a meeting hasn't been decided yet.

A. If

B. That

C. What

D. Whether

6. _______ we are saying is more than _______ we will do.

A. That; that

B. What; what

C. Whatever; that

D. As; as

7. _______ leaves last turns off the light.

A. Who

B. Whoever

C. No matter who

D. Whomever

8. _______ wins the prize may get the car.

A. Who

B. Whom

C. Whomever

D. Whoever

9. _______ a pity that I didn't see you last week.

A. That's

B. What's

C. It's

D. There's

10. _______ she will come is certain.

A. That

B. What

C. /

D. Whether

11. _______ we go swimming every day _______ us a lot of good.

A. If; do

B. That; do

C. That; does

D. If; does

12. _______ has questions can ask the teacher after class.

A. Who

B. Whoever

C. Anybody

D. One

13. _______ is one of the most useful and fascinating divisions of human knowledge is widely accepted.

A. Where chemistry

B. That chemistry

C. What chemistry

D. Chemistry

14. It's known to us _______ chewing gum helps prevent tooth decay.

A. why

B. that

C. whether

D. how

15. Does _______ matter if he can't finish the job on time?

A. this

B. that

C. he

D. it

16. _______ water can be used to _______ electricity is true.

A. That; producing

B. That; produce

C. This; producing

D. This; produces

17. After Yang Liwei succeeded in circling the earth, _______ our astronauts desire to do is walk in space.

A. where

B. what

C. that

D. how

18. It is doubtful _______ he knows it or not.

A. that

B. if

C. what

D. whether

19. _______ caused the accident is still a complete mystery.

A. What

B. That

C. How

D. Where

20. _______ we will have a meeting hasn't been decided yet.

A. If

B. That

C. What

D. Whether

21. It doesn't matter _______ will take charge of the work.

A. who

B. whoever

C. whom

D. whomever

22. _______ is worth doing at all is worth doing well.

A. That

B. Which

C. Whatever

D. It

23. _______ land ownership in some countries is unfair _______ obvious.

A. What; is

B. Whether; are

C. That; is

D. If; is

24. _______ some mammals came to live in the sea is not known.

A. That

B. Since

C. Although

D. How

25. _______ troubles me is _______ my son can finish all _______ he is expected to do.

A. That; whether; /

B. What; if; that

C. That; if; what

D. What; whether; /

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