【正文】 th. 萬(wàn)一他來(lái)，我會(huì)把真相告訴他。 Should the boy e again, I would throw him out. 要是那男孩在來(lái)，我就把他攆出去。 Should that be true, the contract would be canceled. 假如那是真的，合約就該取消。 If the sun were to rise in the west, he would pass the exam. 要是太陽(yáng)從西邊出來(lái)，他就會(huì)通過(guò)考試－－他不可能通過(guò)考試。 If the sun were to disappear, what would the earth be like? 萬(wàn)一太陽(yáng)消失了，地球會(huì)變成什么樣子？ Were I to die tomorrow, what would my children do? 萬(wàn)一明天我死了，我的孩子們將怎么辦呢？If I + Ved, I would ...結(jié)構(gòu)︰If…＋過(guò)去式動(dòng)詞…，主詞＋過(guò)去式助動(dòng)詞（would／should 等）＋原形動(dòng)詞說(shuō)明︰這是與現(xiàn)在事實(shí)相反的假設(shè)句型。過(guò)去式助動(dòng)詞除用 should（用于第一人稱(chēng)）、 would（用于第二、三人稱(chēng)）外，還可用不分人稱(chēng)的 could，might 和 ought to，它們與動(dòng)詞原形結(jié)合起來(lái)構(gòu)成假設(shè)語(yǔ)氣。 If I were free now, I might call on him. 如果我有時(shí)間，我可能會(huì)去看他。 How happy I would be if I were a few inches taller! 要是我再高幾寸，我會(huì)好高興。 If I had binoculars, I could see that et clearly. 如果我有望遠(yuǎn)鏡，我就可以清楚地看見(jiàn)那顆彗星。過(guò)去式動(dòng)詞處有時(shí)亦使用“should＋動(dòng)詞原形”。 It is time he went to bed. 該是他睡覺(jué)的時(shí)間了。 It is time that you reflected upon your mistakes. 該是你反省思過(guò)的時(shí)候了。 It is time for somebody to teach you to behave yourself. 該是有人教你應(yīng)對(duì)進(jìn)退之禮儀的時(shí)候了。if 子句要用過(guò)去完成式，主要子句則要用過(guò)去式助動(dòng)詞（would，should，ought to，might，could）＋have＋過(guò)去分詞。 If I had seen him, I would have told him the truth. 如果我當(dāng)時(shí)看見(jiàn)他，我會(huì)告訴他實(shí)情。 If we had known of your departure, we would have seen you off at the airport. 如果我們事先知道你要離開(kāi)，我們會(huì)到機(jī)場(chǎng)送行。 I might have been incredulous had I not been accustomed to such responses. 若非我已經(jīng)習(xí)慣了這樣的回答，我可能不敢輕易相信。 Had he not saved me, I might have been drowned. 我可能溺死了，若非他救了我。If I had Ved, I would ...結(jié)構(gòu)︰If…h(huán)ad＋過(guò)去分詞…，主詞＋would／should 等＋原形動(dòng)詞＋now／today說(shuō)明︰這是時(shí)態(tài)不一致時(shí)的假設(shè)句型，亦稱(chēng)混合假設(shè)條件句。此類(lèi)主要子句句尾通常有表現(xiàn)在的時(shí)間副詞，如 now，today 等。 If I had been rich ten years ago, I could buy that house today. 如果十年前我有錢(qián)，今天我就能買(mǎi)下那棟房子了。 Had he followed the doctor’s advice, he might be alive now. 當(dāng)時(shí)他要是聽(tīng)了醫(yī)生的建議，現(xiàn)在可能還活著?！癐 wish＋that子句”的句型也可用“I would rather＋that子句”取代。 I wish there were meadows and lambs. 但愿有草地與小羊。 I wish he could tell us. 但愿他能告訴我們。 I wish you had not been caught in the rain yesterday. 但愿昨天你們沒(méi)有淋到雨。 I wish I had known you ten years ago. 真希望十年前就已經(jīng)認(rèn)識(shí)你?！庇眠^(guò)去式，表示與現(xiàn)在事實(shí)相反；若用過(guò)去完成式，則表示與過(guò)去事實(shí)相反。 If only he had been here. 要是他當(dāng)時(shí)在這兒就好了。... as if/as though ...結(jié)構(gòu)︰…as if／as though…現(xiàn)在式／過(guò)去式／過(guò)去完成式說(shuō)明︰此句型意為“彷佛…；好像…一樣”。子句中，可用現(xiàn)在式，以表示事實(shí)；也可用過(guò)去式或過(guò)去完成式，分別表示與現(xiàn)在或過(guò)去事實(shí)相反的假設(shè)語(yǔ)氣。 He walks as if he is drunk. 他走起路來(lái)好像他真的醉了。 The baby opened the book as if he were able to read. 這個(gè)嬰兒打開(kāi)書(shū)本彷佛他會(huì)念書(shū)。 He ran into the room as if he had seen something terrible. 他跑進(jìn)屋子，彷佛他看到什么可怕的東西。It seems/looks as if ...結(jié)構(gòu)︰It seems／looks as if…說(shuō)明︰此句型意為“似乎…”。 It looks as if it is going to rain. 好像要下雨了。 It seems as if he knew everything, but in reality, he is as stupid as can be. 他似乎是個(gè)萬(wàn)事通。 It looks as if she had just e back from outer space. 她看起來(lái)彷佛剛從外層空間回來(lái)似的。 It seemed as if he would never finish the work. 他似乎永遠(yuǎn)完成不了這個(gè)工作。此類(lèi)句構(gòu)專(zhuān)門(mén)用于表示與現(xiàn)在事實(shí)相反的假設(shè)語(yǔ)氣。were 可以提前，省略 if，如例句3。 But for your advice, I should have failed. 要不是你的忠告，我會(huì)失敗的。 If it were not for oxygen and nitrogen in the air, no man could live on the earth. 大氣中如果沒(méi)有氧和氮，人就無(wú)法生存于地球了。 Without newspaper, we would get behind the times. 要不是報(bào)紙，我們都趕不上時(shí)代了。 Were it not for his help, I could not finish the ，我就不能完成這件工作。If it had not been for ...結(jié)構(gòu)︰if it had not been for＋名詞／子句，主詞＋would／should 等＋原形動(dòng)詞…說(shuō)明︰此句型意為“若非（有）…”。 If it had not been for his help, I should have failed. 如果沒(méi)有他的幫忙，我應(yīng)該已經(jīng)失敗。If it had not been for these experiments, the improvement of the machine would have been impossible. 要不是這些實(shí)驗(yàn)，這部機(jī)器也許就不可能改良了。 If it had not been that he was here, I would have punished you. 要不是他在場(chǎng)，我當(dāng)時(shí)就會(huì)處罰你。其后接 that子句時(shí)，該子句里的動(dòng)詞要用原形或“should＋動(dòng)詞”。 The mittee moved that the meeting (should) be adjourned. 委員提議休會(huì)。 The employees demand that their salaries be raised. 員工們要求加薪。 His father ordered that he (should) keep a diary in English. 他的父親規(guī)定他要用英文寫(xiě)日記。 He insisted that I (should) apologize to her. 他堅(jiān)持我應(yīng)該向她道歉。 His father insisted that they (should) move to the country. 他爸爸堅(jiān)持他們應(yīng)該搬到鄉(xiāng)下。that子句中只能用助動(dòng)詞 should，不可用 must，而 should 往往予以省略。 It is essential that he get up early. 他有必要早起。 It is desirable that we (should) provide for the poor at Christmas. 在圣誕節(jié)施舍窮人是可喜的事。 It is important that he not do it. 他不該做那事是有必要的。 It is proper that such a bad man be punished severely. 這么壞的人受重罰是應(yīng)該的。祈使句代替 if 子句進(jìn)行評(píng)說(shuō)，提出要求，訂立協(xié)議，提供建議或威脅等。 Provide the materials and we’ll do the job. 提供材料，我們就做這活。 Put that down or else I’ll smack you. 把它放下，不然我就揍你。 Fail to pay and they’ll cut off the electricity. 你（如果）不付款，他們就要斷電。Unless ...結(jié)構(gòu)︰Unless＋子句，主要子句說(shuō)明︰此句型意為“除非…”?？傮w上看，unless 的語(yǔ)氣強(qiáng)于 if ... not ...，而且有時(shí)較為常用，例如在最后通牒中。 Unless the management improves their offer, there’ll be a strike. 除非資方做出進(jìn)一步的建議，否則將舉行罷工。Provided/Providing (that) ....結(jié)構(gòu)︰Provided／provided（that）＋子句，S＋V ...說(shuō)明︰此句型意為“如果…”。 Provided/Providing (that) you clear your desk by this evening, you can have tomorrow off. 如果你到今晚把手頭上的工作做完，你明天就可以休息。As/So long as引導(dǎo)一個(gè)條件假設(shè)句，其功能相當(dāng)于 if。 As long as you drive carefully, you will be very safe. 如果你開(kāi)車(chē)小心，你就會(huì)很安全。 As long as live, I will help you. 只要我活著，我都會(huì)幫助你。 We’ll ship the goods at an early time as long as there is a ，我們就盡早裝貨。Suppose/Supposing (that) ...結(jié)構(gòu)︰Suppose/Supposing （that）＋子句，S＋V ...說(shuō)明︰此句型意為“如果…，假使…”。 Suppose/Supposing (that) we miss the train, what shall we do? 如果我們誤了火車(chē)，我們將怎么辦？What if/Say ...結(jié)構(gòu)︰What if/Say＋子句，S＋V ...說(shuō)明︰此句型意為“假設(shè)…”。 What if/Say he goes home before us and can’t get in? What will he do then? 假設(shè)他在我們之前趕到家而又進(jìn)不去呢？那他怎么辦呢？ What if/Say you were to run out of money? What would you do? 假設(shè)你的錢(qián)用完了呢？你將怎么辦呢？With luck ...結(jié)構(gòu)︰With luck，＋主要子句說(shuō)明︰With luck 為含蓄假設(shè)條件句（即不用 if 直接引導(dǎo)）。 With luck, we’ll be there by ，我們明天將到達(dá)那兒。（=If she is lucky）Given time ...結(jié)構(gòu)︰Given time，＋主要子句說(shuō)明︰此為含蓄假設(shè)條件句（即不用 if 直接引導(dǎo)）。Given time, they will probably ，他們