2024年12月大學(xué)習(xí)英語(yǔ)四級(jí)基礎(chǔ)語(yǔ)法備考

虛擬語(yǔ)氣

1. 表示目前/過(guò)去/以后狀況的虛擬條件句

虛擬條件句主要有三種結(jié)構(gòu)：

1)表示與目前狀況相反：主句謂語(yǔ)用“would / could / might +動(dòng)詞原形”，從句謂語(yǔ)用“動(dòng)詞的一般過(guò)去時(shí)”。

If I were you, I would not accept his offer.

If I had time, I would certainly go to the cinema with you.

2) 表示與過(guò)去狀況相反：主句謂語(yǔ)用“would / could / might + have +過(guò)去分詞”，從句謂語(yǔ)用過(guò)去完成時(shí)。

If I had got up a little earlier, I wouldn’t have missed the train.

If I had been more careful, I might have passed that exam.

3) 表示與以后狀況相反：主句謂語(yǔ)用“would / could / might +動(dòng)詞原形”，從句謂語(yǔ)用“were +動(dòng)詞不定式”或“should +動(dòng)詞原形”。

If I were to do the job, I would not be able to have enough time to study.

If it should rain tomorrow, I would not go out with you.

2. 虛擬條件句連接詞if的省略

假如虛擬條件句的從句中含有were, had, should, could等詞時(shí)，可以省略連接詞if，但這個(gè)時(shí)候需要把were, had, should, could等詞移到主語(yǔ)前面，形成倒裝。這種句型主要用于書(shū)面形式。

Were I to do the job, I would finish doing it within two weeks.

Had it not been for his help, we couldn’t have arrived there on time.

Should it rain tomorrow, I would stay at home.

3. wish后賓語(yǔ)從句中的謂語(yǔ)構(gòu)成

動(dòng)詞wish后的賓語(yǔ)從句表示未達(dá)成的或不可能達(dá)成的愿望，其賓語(yǔ)從句中的謂語(yǔ)動(dòng)詞要用虛擬語(yǔ)氣，有以下三種構(gòu)成形式。

1) 表示目前不可能達(dá)成的愿望，賓語(yǔ)從句中的謂語(yǔ)動(dòng)詞用一般過(guò)去時(shí)。。

I wish I had enough money to buy a car.

I wish I were as young and energetic as you.

2) 表示過(guò)去未能達(dá)成的愿望，賓語(yǔ)從句中的謂語(yǔ)動(dòng)詞用過(guò)去完成時(shí)或“would / could + have +過(guò)去分詞 ”。

I wish I hadn’t made such a mistake.

I wish I could have done it better.

3) 表示以后不可能達(dá)成的愿望，賓語(yǔ)從句中的謂語(yǔ)動(dòng)詞用“would / should +動(dòng)詞原形”。

I wish I would not get old.

I wish I could travel around the world one day.

4. 某些動(dòng)詞后的賓語(yǔ)從句中謂語(yǔ)動(dòng)詞要用虛擬語(yǔ)氣

在一些動(dòng)詞后面的賓語(yǔ)從句中，謂語(yǔ)動(dòng)詞要用虛擬語(yǔ)氣。這個(gè)時(shí)候，謂語(yǔ)動(dòng)詞用動(dòng)詞原形或should +動(dòng)詞原形。這種動(dòng)詞一般表示命令，需要，決定，建議，倡導(dǎo)等定義，主要有：advise, ask, command, decide, demand, desire, direct, insist, move, order, propose, recommend, request, require, suggest,等。

The workers demanded that their wages be raised by 10 per cent.

The teacher decided that you do the experiment first.

5. 某些名詞后的表語(yǔ)從句和同位語(yǔ)從句中謂語(yǔ)動(dòng)詞要用虛擬語(yǔ)氣

在一些名詞后面的表語(yǔ)從句和同位語(yǔ)從句中，謂語(yǔ)動(dòng)詞要用虛擬語(yǔ)氣。這個(gè)時(shí)候，謂語(yǔ)動(dòng)詞用動(dòng)詞原形或should +動(dòng)詞原形。這種名詞一般表示命令，需要，決定，建議，倡導(dǎo)等定義，主要有：advice, idea, instruction, motion, order, plan, proposal, recommendation, request, requirement, suggestion,等。

My suggestion is that we send for a doctor immediately.

He gave the order that they do the experiment again.

6. 錯(cuò)綜時(shí)間條件句

條件從句表示的動(dòng)作和主句表示的動(dòng)作，有時(shí)發(fā)生的時(shí)間是不同的.如從句是對(duì)過(guò)去狀況的假設(shè)，而主句可能是對(duì)目前正在進(jìn)行狀況的假設(shè)。 這種句子稱(chēng)為錯(cuò)綜時(shí)間條件句.

If the weather had been more favourable, the crops would be growing still better.

7. 某些主語(yǔ)從句中的謂語(yǔ)動(dòng)詞要用虛擬語(yǔ)氣

某些表示命令，需要，決定，建議，倡導(dǎo)與“重要程度”和“緊迫性”等定義的主語(yǔ)從句中謂語(yǔ)動(dòng)詞要用虛擬語(yǔ)氣。這個(gè)時(shí)候，謂語(yǔ)動(dòng)詞用動(dòng)詞原形或should +動(dòng)詞原形。這種主語(yǔ)從句一般由 “It is + 形容詞/過(guò)去分詞 + that引導(dǎo)的從句”構(gòu)成。該結(jié)構(gòu)中，常見(jiàn)的形容詞主要有：advisable, appropriate, desirable, essential, imperative, important, necessary, obligatory, proper, urgent, vital等;常見(jiàn)的過(guò)去分詞主要有：arranged, decided, demanded, desired, ordered, proposed, recommended, requested, suggested等。

It is necessary that you sTOP smoking so heavily.

It is arranged that you enter for this competition.

8. as if / though引起的從句

當(dāng)as if / though引起的從句所表達(dá)的內(nèi)容完全與實(shí)質(zhì)狀況相反或者純粹是一種假設(shè)時(shí)，一般要用虛擬語(yǔ)氣。假如從句表示與目前的事實(shí)相反，謂語(yǔ)動(dòng)詞用一般過(guò)去時(shí);假如從句表示與過(guò)去的事實(shí)相反，謂語(yǔ)動(dòng)詞用過(guò)去完成時(shí);假如從句表示與以后的事實(shí)相反，謂語(yǔ)動(dòng)詞用would + 動(dòng)詞原形;

They talked as if they had been friends for years.

I remember the whole thing as if it happened yesterday.

It looks as if it might rain.

Note: 假如as if / though引起的從句所表達(dá)的內(nèi)容被看作是事實(shí)或者大概是真實(shí)的，則要用陳述語(yǔ)氣。

It seems as if it is going to rain.

The meat tastes as if it has already gone bad.

9. lest, for fear that和 in case引起的從句

當(dāng)lest, for fear that和 in case表示“以免，以防，生怕，惟恐”等時(shí)，在它們引起的從句中，謂語(yǔ)動(dòng)詞常用should + 動(dòng)詞原形。

He ran away lest he should be seen.

He’s working hard for fear that he should fall behind.

He left early in case he should miss the last train.

10. If only引出的從句

If only引出的從句用以表達(dá)感嘆性的愿望，常譯為“如果…就好了”。If only從句常常省略結(jié)果主句，且主要用在虛擬語(yǔ)氣中，即從句的謂語(yǔ)動(dòng)詞用一般過(guò)去時(shí)表示目前或以后不可能達(dá)成的愿望，或用過(guò)去完成時(shí)表示過(guò)去沒(méi)達(dá)成的愿望。

If only the rain would sTOP.

If only I’d listened to my parents.

Note: if only引出的句子偶爾也可用陳述語(yǔ)氣，但考生需小心的是，在各類(lèi)測(cè)試中一般都以用虛擬語(yǔ)氣為正確答案。

11. would rather引出的從句

would rather意為“寧可”，接從句時(shí)常省略關(guān)系代詞that。would rather后的從句要用虛擬語(yǔ)氣，即從句謂語(yǔ)動(dòng)詞用一般過(guò)去時(shí)表示目前或以后的愿望，用過(guò)去完成時(shí)表示與過(guò)去事實(shí)相反的愿望。

I’d rather you told me the truth.

I would rather you came tomorrow than today.

I’d rather you hadn’t told me about it.

12. It is time 句型

該句型表示“該做…”，其后的定語(yǔ)從句中的謂語(yǔ)動(dòng)詞要用虛擬語(yǔ)氣表示。在測(cè)試中從句的謂語(yǔ)動(dòng)詞用一般過(guò)去時(shí)。

It is time that we went to bed.

It is high time that somebody taught you to behave yourself.

13. 表示猜測(cè)的幾種不一樣的辦法及意義

一些情態(tài)動(dòng)詞與動(dòng)詞的完成式連用可以表示對(duì)過(guò)去狀況的猜測(cè)或者未達(dá)成的可能性。

1) could have + 過(guò)去分詞

A. 表示對(duì)過(guò)去可能發(fā)生的事情的推斷，意為，“可能做了某事”。

He couldn’t have seen her yesterday.

They could have lost their way.

B. 表示某事在過(guò)去本大概發(fā)生，但事實(shí)上并未發(fā)生，意為，“本可以做某事”。

We could have started a little earlier.

I could have killed her. It was a narrow escape.

2) may have + 過(guò)去分詞

A. 表示對(duì)過(guò)去狀況的推斷，意為，“可能已做某事”。

He may have heard the news.

I might have come to a wrong conclusion.

B. 表示一種未達(dá)成的可能性，即本可以做某事，而事實(shí)上并沒(méi)做，有時(shí)含有抱怨的口吻。

It was a narrow escape. You might have killed yourself.

A lot of men died who might have been saved.

3) must have + 過(guò)去分詞

表示邏輯上的勢(shì)必性，即根據(jù)某些現(xiàn)象判斷過(guò)去一定發(fā)生過(guò)的某事。

She must have made a big mistake.

The city at one time must have been prosperous, for it enjoyed a high level of civilization.

4) needn’t have + 過(guò)去分詞

表示過(guò)去不必做某事，但已經(jīng)做了，即本可不必做某事。

You needn’t have woken me up. I don’t have to go to work today.

He needn’t have watered the flowers, for it is going to rain.

5) should / ought to have + 過(guò)去分詞

表示過(guò)去應(yīng)該做某事而事實(shí)上沒(méi)做。

You should / ought to have done what your parents told you.

You should / ought to have been more careful.

6) shouldn’t / oughtn’t to have + 過(guò)去分詞

表示過(guò)去不應(yīng)該做某事而事實(shí)上卻做了。

You shouldn’t / oughtn’t to have crossed the road when the lights were red.

They shouldn’t / oughtn’t to have left so soon.

7) would have + 過(guò)去分詞

表示對(duì)目前或以后某時(shí)之前業(yè)已完成的動(dòng)作的推斷�？勺g為，“可能”、“或許”、“想來(lái)”。

He would have arrived by now.

She would have recovered by then.