2017年高考英語語法必考知識點：主語從句

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▲高考英語語法必考知識點：主語從句

1、常規(guī)主語從句，即句子在復合句中充當一個主語

主語從句的時態(tài)不受主句時態(tài)的影響和限制

（1）That he finished writing the composition in such a short time surprised us all.

（2）Whether we will go for an outing tomorrow remains unknown.

（3）Who will be our monitor hasn't been decided yet.

（4）Whom we must study for is a question of great importance.

（5）What caused the accident remains unknown.

（6）Whatever you did is right.

（7）Whom the watch belongs to is unknown.

（8）What we need is time.

（9）What we need are good doctors.

2、為了防止句子頭重腳輕，通常把形式主語it放在句首位置，真正主語擱置于句末

（1）It is certain that he will win the match.

（2）It is true that he has made a very important discovery in chemistry.

（3）It is very likely that they will hold a meeting.

（4）It is strange that he should do that.

（5）It is important that we all should attend the meeting.

（6）It is strange that the man should have stuck to his silly ideas.

（7）It is a pity that we won't be able to go to the south to spend our summer vacation.

（8）It is still a mystery what caused the accident.

（9）It is said that he has gone to shanghai.(=He is said to have gone to shanghai)

（10）It is known to all that the gun powder was first invented by the Chinese.

（11）It is suggested that the work should be done with great care.

（12）It happened that the two cheats were there. (=The two cheats happened to be there)

小結:

（1）為避免頭重腳輕，常以形式主語it引導從句。 It+形式主語謂語+從句。

（2）由于主語從句一般被認為是單數(shù)形式，形式主語的謂語動詞、be動詞+表語 均為單數(shù)第三人稱形式或過去式.

（3）引導主語從句連詞有that,whether,who,what,whatever等

（4）連詞位于句首不能省略

（5）主語從句大多數(shù)情況下視為第三人稱單數(shù)，但也有例外。

注意：當what引導的名詞性分句作主語時，主謂一致問題極為復雜。

▲高考英語語法必考知識點：主語從句的時態(tài)規(guī)則

1）、主句謂語動詞是現(xiàn)在或?qū)頃r，從句謂語動詞可以用任何需要的時態(tài)。

I wonder what he is doing now.

Do you know when and where he was born

I'll write to tell him where I 'll meet him.

2）、主句謂語動詞是過去時，從句謂語動詞一般需用過去時。

（1）從句與主句的謂語動作同時發(fā)生，從句用一般過去時或過去進行時。

I thought that he studied hard.

He told me his son was watching TV.

（2）從句謂語動作在主句謂語動作之后，從句用過去將來時。

He said he would spend his holidays in Qingdao.

（3）從句謂語動作在主句謂語動作之前，從句用過去完成時。

They told me they had waited for me half an hour.

（4）從句如果有表示過去某一具體時間的狀語，仍用過去時。

She told me her brother died in 1945.

3)客觀的條件，從句時態(tài)不受絲毫影響。

（1）從句說明的是不受時間限制的事實或真理（客觀真理）。

The teacher told us that the earth turns from west to east.

He said Asia is the largest continent.

It was true that water freezes at thirty-two degrees Fahrenheit.

（2）當從句表示的是反復出現(xiàn)的時態(tài)不變。

She told me that she gets up at six o'clock every morning.

He asked me when the train usually starts.

（3）當從句是用來表達解釋科技內(nèi)容時時態(tài)不變。

（4）當從句的謂語動作仍在繼續(xù)時，或者表示現(xiàn)在仍在的狀態(tài)時，時態(tài)不變。

He said that the workers in that factory are trying to fulfill the task in time.

She told me the other day that she is only 10.

（5）當從句的動作狀態(tài)還未發(fā)生，要用一般式表示。強調(diào)與現(xiàn)在的聯(lián)系。

He said he will wait for me this evening.

▲高考英語語法必考知識點：主語從句的連接詞

1）從屬連詞（從句中不充當成分，只起連接作用）：that，whether等. that 引導主語從句只起引導作用，本身無意義，在主語從句中不充當任何成分，但不能省略。注意:

已確定的事由that引導;沒決定的事由whether引導. That he will come is certain. Whether it will please them is not easy to say.

2)連接代詞（在從句中充當主語，賓語，或表語）who ，what ，which, whatever, whichever, whoever What seems easy to some people seems difficult to others. Which side will win is not clear. Whoever comes is welcome. Whatever I have is yours. 3)連接副詞 when（從句中作時間狀語）where （從句中作地點狀語）how （從句中作方式狀語）why（從句中作原因狀語）Why he did it remains a mystery. When they will start is not known yet. How he became a great scientist is known to us all.

▲高考英語語法必考知識點：主語從句后置

為了避免主語冗長,句子頭重腳輕,經(jīng)常用it作形式主語,主語從句放在后面作真正的主語. 如：

1）. That we shall be late is certain.

-- It’s certain that we shall be late.

2）. That the earth is round is known to all.

-- It’s known to all that the earth is round.

用it作形式主語的that從句有以下幾種不同的搭配： 1.It + be + 形容詞 ＋ that從句 2.It + be + -ed分詞 ＋ that從句

▲高考英語語法必考知識點：主語從句需注意的問題

1）.“if” 通常不能引導主語從句，要用“whether”引導。

2）.主語從句中用陳述句語序

3）.主語從句的 “that” 一般不能省。That price will go up is certain.

4）.主語從句后謂語動詞用第三人稱單數(shù) That they haven’t phoned is strange.

5）.主語從句在句首時，必須由連接詞引導，不能省略這些連接詞；但是如果用it做形式主語，而把主語從句放在句末時，從屬連詞that可以省略。

6）.如果主語從句放在句首，不能用if引導，但是如果用it 做形式主語，而把主語從句放在句末時，也可以用if引導. 誤：If Mary really heard him is really doubtful. 正：It was doubtful if Mary really heard him.

7）.用于It is important / natural / necessary / impossible that...句型中, 主語從句謂語動詞用“（should） + 動詞原形”的形式, should可以省略。 例： It is imporant we (should) believe him.

8）. 在it + be + suggested/ advised/ required/ ordered/ requested/ insisted that…句型中從句謂語動詞也用“（should） + 動詞原形”的形式.例： It is suggested that we (should) go there by bus.

9）. what 與that 在引導主語從句時的區(qū)別

what 引導主語從句時在句時在從句中充當句子成分，如主語．賓語．表語，而that 則不然。例如： A： What you said yesterday is right.

What在此引導主語從句,又做said的賓語 B： That she is still alive is a consolation。That只起連接作用,不做成分。

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