2010年12月大學(xué)英語(yǔ)四級(jí)考試常用語(yǔ)法精選(20)

　　虛擬語(yǔ)氣

　　1. 表示現(xiàn)在/過(guò)去/將來(lái)情況的虛擬條件句

　　虛擬條件句主要有三種結(jié)構(gòu)：

　　1)　表示與現(xiàn)在情況相反：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)”(動(dòng)詞be的過(guò)去式一律用were)。

　　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)去情況相反：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) 表示與將來(lái)情況相反：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

　　如果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，但這時(shí)必須把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)從句表示未實(shí)現(xiàn)的或不可能實(shí)現(xiàn)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) 表示現(xiàn)在不可能實(shí)現(xiàn)的愿望，賓語(yǔ)從句中的謂語(yǔ)動(dòng)詞用一般過(guò)去時(shí)。(be的過(guò)去式為were)。

　　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)去未能實(shí)現(xiàn)的愿望，賓語(yǔ)從句中的謂語(yǔ)動(dòng)詞用過(guò)去完成時(shí)(had +過(guò)去分詞)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) 表示將來(lái)不可能實(shí)現(xiàn)的愿望，賓語(yǔ)從句中的謂語(yǔ)動(dòng)詞用“would / should (could, might) +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。這時(shí)，謂語(yǔ)動(dòng)詞用動(dòng)詞原形或should +動(dòng)詞原形。這類(lèi)動(dòng)詞一般表示命令，要求，決定，建議，主張等概念，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 (should) 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。這時(shí)，謂語(yǔ)動(dòng)詞用動(dòng)詞原形或should +動(dòng)詞原形。這類(lèi)名詞一般表示命令，要求，決定，建議，主張等概念，主要有：advice, idea, instruction, motion, order, plan, proposal, recommendation, request, requirement, suggestion,等。

　　My suggestion is that we (should) send for a doctor immediately.

　　He gave the order that they (should) 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)間是不一致的.如從句是對(duì)過(guò)去情況的假設(shè)，而主句可能是對(duì)現(xiàn)在正在進(jìn)行情況的假設(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，要求，決定，建議，主張以及“重要性”和“緊迫性”等概念的主語(yǔ)從句中謂語(yǔ)動(dòng)詞要用虛擬語(yǔ)氣。這時(shí)，謂語(yǔ)動(dòng)詞用動(dòng)詞原形或should +動(dòng)詞原形。這類(lèi)主語(yǔ)從句一般由 “It is (was) + 形容詞/過(guò)去分詞 + that引導(dǎo)的從句”構(gòu)成。該結(jié)構(gòu)中，常用的形容詞主要有：advisable, appropriate, desirable, essential, imperative, important, necessary, obligatory, proper, urgent, vital等;常用的過(guò)去分詞主要有：arranged, decided, demanded, desired, ordered, proposed, recommended, requested, suggested等。

　　It is necessary that you (should) stop smoking so heavily.

　　It is arranged that you (should) 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)際情況相反或者純粹是一種假設(shè)時(shí)，通常要用虛擬語(yǔ)氣。如果從句表示與現(xiàn)在的事實(shí)相反，謂語(yǔ)動(dòng)詞用一般過(guò)去時(shí);如果從句表示與過(guò)去的事實(shí)相反，謂語(yǔ)動(dòng)詞用過(guò)去完成時(shí);如果從句表示與將來(lái)的事實(shí)相反，謂語(yǔ)動(dòng)詞用would (might, could) + 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: 如果as if / though引起的從句所表達(dá)的內(nèi)容被看作是事實(shí)或者有可能是真實(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“要是…就好了”。If only從句經(jīng)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)表示現(xiàn)在或?qū)��?lái)不可能實(shí)現(xiàn)的愿望，或用過(guò)去完成時(shí)表示過(guò)去沒(méi)有實(shí)現(xiàn)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使用陳述語(yǔ)氣，但考生須注意的是，在各類(lèi)測(cè)試中一般都以用虛擬語(yǔ)氣為正確答案。