If + Present Tense ， S + will/shall + V

結(jié)構(gòu)︰If+現(xiàn)在式，S+未來(lái)式

說(shuō)明︰if 子句用現(xiàn)在式，表示須具備的條件，主句用未來(lái)式表示可能的結(jié)果，整句含意為如果，那么。will 用于所有的人稱(chēng)，在 I 和 we 之后可用 shall 代替 will.若主句的主詞為 I 或 we 時(shí)，可以用 shall 代替 will.像 if necessary(如果需要)，if possible(如果可能)，if so(如果這樣)等固定詞組實(shí)際上是省略了的 if 子句。

If I lose my job， I will/shall go abroad. 如果我失業(yè)了，我就出國(guó)。

If I have a headache， I will take an aspirin. 如果我頭痛，我就服一片阿斯匹林。

If it rains， we will stay at home. 如果下雨，我們將待在家里。

If the weather clears， well go for a walk. 如果天晴，我們就去散步。

If the weather doesnt clear， we wont go for a walk. 如果天不晴，我們就不去散步。

Inflation may be rising， if (it is) so， prices will go up.

通貨膨脹率可能上升。如果是這樣，物價(jià)就會(huì)上漲。

If possible， She wants to go with us. 可能的話，她想跟我們一起去。

Sterling may fall， if (this should be) so， interest rates will rise.

英國(guó)貨幣可能貶值，如果果真如此，利率就會(huì)上升。

If + Present Tense ， S + Modal Verb

結(jié)構(gòu)︰If + 現(xiàn)在式，主詞+情態(tài)助動(dòng)詞

說(shuō)明︰本句型實(shí)為句型之變體。之所以用情態(tài)助動(dòng)詞，主要是因?yàn)檎f(shuō)話者對(duì)可能的結(jié)果不是太肯定或者是想表達(dá)例如必要的意思。

If it is fine tomorrow， we can go out. 如果明天天氣好，我門(mén)可以出門(mén)。

If it is fine tomorrow， we could go out. 如果明天天氣好，我門(mén)能夠出門(mén)。

If it is fine tomorrow， we may go out. 如果明天天氣好，我門(mén)可能出門(mén)。

If it is fine tomorrow， we might go out. 如果明天天氣好，我門(mén)可能出門(mén)。

If it is fine tomorrow， we should go out. 如果明天天氣好，我門(mén)宜于出門(mén)。

If it is fine tomorrow， we ought to go out. 如果明天天氣好，我門(mén)宜于出門(mén)。

If it is fine tomorrow， we must go out. 如果明天天氣好，我門(mén)必須出門(mén)。

If I should ， Imperative Sentence.

結(jié)構(gòu)︰If I+should +祈使語(yǔ)氣

說(shuō)明︰代替，增加了條件的不確定性。本句型常用在想禮貌地提出要求或建議，或者想圓通地告訴他人該做什么事的場(chǎng)合。用 should 起始句子即可不用 if 而表示條件。這種用法比較正式，常用于諸如公函之中，而不用于日常會(huì)話。

If you should see him， please give him my regards. 如果你見(jiàn)到他，請(qǐng)代我向他致意。

Should you see him， please give him my regards. 如果你見(jiàn)到他，請(qǐng)代我向他致意。

If you should happen to see him， please give him my regards.

如果你萬(wàn)一見(jiàn)到他，請(qǐng)代我向他致意。

Should you happen to see him， please give him my regards.

如果你萬(wàn)一見(jiàn)到他，請(qǐng)代我向他致意。

If you should write to her， send her my love. 如果你給她寫(xiě)信，請(qǐng)代我向她問(wèn)候。

Should you not wish our agent to call， please let us know.

你若不希望我們的代理人去造訪，請(qǐng)告之。

Should you be interested in our offer， please contact us.

你若對(duì)我們的報(bào)價(jià)感興趣，請(qǐng)與我們聯(lián)系。

If I should ， I will

結(jié)構(gòu)︰Ifshould，would(will)/should(shall)等+原形動(dòng)詞

說(shuō)明︰這是表示與未來(lái)事實(shí)相反的假設(shè)句型，if 子句要用助動(dòng)詞 should，譯成萬(wàn)一。should可置于主詞前，將 if 省略。主要子句助動(dòng)詞則視可能性做變化：若可能性低，則為過(guò)去式，若可能性高，則為現(xiàn)在式。should 可以提前，而將 if 省略。

If he should come， I would tell him the truth. 萬(wàn)一他來(lái)，我會(huì)把真相告訴他。

If he should come， I will tell him the truth. 萬(wàn)一他來(lái)，我一定會(huì)把真相告訴他。

Should the boy come again， I would throw him out. 要是那男孩在來(lái)，我就把他攆出去。

If it should rain， our plan would be spoiled. 萬(wàn)一下雨，我們的計(jì)劃就泡湯了。

Should that be true， the contract would be canceled. 假如那是真的，合約就該取消。

Should another world war break out， what would become of human beings?

萬(wàn)一另一次世界大戰(zhàn)爆發(fā)，人類(lèi)將會(huì)發(fā)生什么事?

If I were to ， I

結(jié)構(gòu)︰Ifwere to，would/should 等+原形動(dòng)詞

說(shuō)明︰這也是表示與未來(lái)狀況相反的假設(shè)句型，與if should， 大致相同，但if were to所表示的可能性更低，通常用以表示與真理相反的假設(shè)語(yǔ)氣.

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 I were to be born again， I would like to be a bird. 我要是再活一次，我想當(dāng)一只鳥(niǎo)。

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 + V-ed， 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。if 子句中的 動(dòng)詞，不論主詞為第幾人稱(chēng)，一律用 were，were 可置于主詞前面，而省略 if.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 knew his address， I could write to him. 如果我知道他的住址，我會(huì)寫(xiě)信給他。

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。

If you were in my shoes (=Were you in my shoes)， what would you do?

如果你站在我的立場(chǎng)，你會(huì)怎么做?

Were I rich enough， I would buy a sports car. 如果我有足夠的錢(qián)，我就買(mǎi)一輛賽車(chē)了。

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 a car， I could take her for a drive. 如果我有車(chē)， 我就帶她去兜風(fēng)了。

If I had binoculars， I could see that comet clearly.

如果我有望遠(yuǎn)鏡，我就可以清楚地看見(jiàn)那顆彗星。

It is time that

結(jié)構(gòu)︰It is(high)time+(that)+主詞+過(guò)去式動(dòng)詞

說(shuō)明︰此句型意為已經(jīng)到了的時(shí)間了。過(guò)去式動(dòng)詞處有時(shí)亦使用should+動(dòng)詞原形。that 子句也能用 to 不定詞來(lái)表示。

It is time he went to bed. 該是他睡覺(jué)的時(shí)間了。

It is time that you left for the duty. 該你當(dāng)班了。

It is time that you reflected upon your mistakes. 該是你反省思過(guò)的時(shí)候了。

It is high time he should come to our house for dinner.已經(jīng)到了他該上咱家吃晚飯的時(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 I had V-ed， I would have

結(jié)構(gòu)︰Ifhad+過(guò)去分詞，主詞+would/should 等+have+過(guò)去分詞

說(shuō)明︰這是與過(guò)去事實(shí)相反的假設(shè)句型子句要用過(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)去分詞子句中的 had可置于主詞前面，而省略 If.

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。

I could have finished the task if I had had more time.

如果當(dāng)時(shí)我能有多一點(diǎn)時(shí)間，我就能完成這項(xiàng)任務(wù)。

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 someone had been with him， he might not have been drowned.

如果有人在他旁邊，或許他就不會(huì)溺死。

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 apologize to her， she would not have forgiven him.

她(那時(shí))不會(huì)原諒他，若非他道了歉。

Had he not saved me， I might have been drowned. 我可能溺死了，若非他救了我。

Had I proposed to you， would you have married me?

我要是當(dāng)年向你求婚，你會(huì)答應(yīng)嫁給我嗎?

Had you not helped us， we should have canceled this transaction.

假如沒(méi)有你的幫助，這筆生意早就告吹了。

If I had V-ed， I would

結(jié)構(gòu)︰Ifhad+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。即：if 子句若與過(guò)去事實(shí)相反，用過(guò)去完成式而主要子句若與現(xiàn)在事實(shí)相反，則用過(guò)去式助動(dòng)詞表示。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 he had worked harder when young， he would be well off now.

如果他年輕時(shí)多努力一點(diǎn)，現(xiàn)在就能過(guò)得舒服些。

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 told the truth， he wouldnt be punished now.如果他當(dāng)時(shí)肯說(shuō)實(shí)話，現(xiàn)在就不會(huì)受罪了。

Had he followed the doctors 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。

I wish + V-ed

結(jié)構(gòu)︰I wish+(that)+主詞+動(dòng)詞過(guò)去式/過(guò)去完成式(had+過(guò)去分詞)

說(shuō)明︰I wish 之后以 that 子句受詞時(shí)，該子句動(dòng)詞一定要用假設(shè)語(yǔ)氣：若動(dòng)詞用過(guò)去式，表示與現(xiàn)在事實(shí)相反的愿望;若用過(guò)去完成式，則表示與過(guò)去事實(shí)相反的愿望。I wish+that-子句的句型也可用I would rather+that-子句取代。而 I hope 之后以 that 子句受詞時(shí)，該子句用一般時(shí)態(tài).

I wish there were meadows and lambs. 但愿有草地與小羊。

I wish I were as tall as you. 但愿我像你一樣高。

I wish he could tell us. 但愿他能告訴我們。

I wish (=I would rather) he could come tomorrow. 但愿他明天能來(lái)。

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 you had not told the truth. 但愿你沒(méi)有說(shuō)實(shí)話。

I wish I had known you ten years ago. 真希望十年前就已經(jīng)認(rèn)識(shí)你。

If only + V-ed

結(jié)構(gòu)︰If only+過(guò)去式/過(guò)去完成式

說(shuō)明︰此句型意為要是就好了。用過(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 I had a rich father. 要是我有個(gè)有錢(qián)的爸爸就好了。

If only he had been here. 要是他當(dāng)時(shí)在這兒就好了。

If only I had another chance. 要是我再有一次機(jī)會(huì)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。as if，as though 是副詞連接詞，引導(dǎo)副詞子句子句中，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 speaks like that as if he doesnt want to attend the meeting.他那樣說(shuō)話，似乎不想?yún)⒓訒?huì)議。

He walks as if he is drunk. 他走起路來(lái)好像他真的醉了。

He felt as if he almost wished to kill them. 他感覺(jué)彷佛幾乎要?dú)⒌羲麄儭?/p>

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)。

The nurse attends on the patient as if he were her father.

這護(hù)士照顧這位病人彷佛在照顧她爸爸似的。

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。

She looks as if nothing had happened to her. 她當(dāng)時(shí)看起來(lái)好像什么事都沒(méi)發(fā)生似的。

It seems/looks as if

結(jié)構(gòu)︰It seems/looks as if

說(shuō)明︰此句型意為似乎。本句型中的 as if 子句可用以表示事實(shí)，或假設(shè)語(yǔ)氣.

It looks as if it is going to rain. 好像要下雨了。

It seems as if he knows everything. 他似乎是個(gè)萬(wàn)事通。

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。其實(shí)他是再愚蠢不過(guò)了。

It looks as if she had just come 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 had finished the work. 他似乎已經(jīng)完成了這個(gè)工作。

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。

If it were not for

結(jié)構(gòu)︰if it were not 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)。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.亦可用but for+名詞或without+名詞代替。were 可以提前，省略 if，如例句3.

If it were not for his presence， I would punish you. 要不是他在場(chǎng)，我會(huì)處罰你的。

But for your advice， I should have failed. 要不是你的忠告，我會(huì)失敗的。

But for music (=Were it not for music)， life would be dull. 要不是音樂(lè)，人生會(huì)很無(wú)聊。

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 air， all living things would die. 若非空氣，所有的生物都會(huì)死亡。

Without newspaper， we would get behind the times. 要不是報(bào)紙，我們都趕不上時(shí)代了。

I should be lonely， were it not for the birds and the flowers. 我會(huì)寂寞，若非有鳥(niǎo)也有花。

Were it not for his help， I could not finish the work.若非有他的幫助，我就不能完成這件工作。

Were it not for science， we could not live a comfortable live.

若非科學(xué)，我們無(wú)法過(guò)著舒適的生活。

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