1、真實(shí)條件句和非真實(shí)條件句（虛擬語氣 ）英語中的條件句分為真實(shí)條件句和非真實(shí)條件句。一、真實(shí)條件句 ：表示現(xiàn)實(shí)情況中可能實(shí)現(xiàn)的情況。真實(shí)條件句中的謂語動詞一般用一般現(xiàn)在時(shí)代替一般將來時(shí)，用一般過去式代替過去將來時(shí)。例如：If it rains tomorrow, I will stay at home.They said they would let us know if they heard any news about him.時(shí)態(tài)語序【詳解】條件狀語從句表示主句動作發(fā)生的條件，通常由 if 來引導(dǎo)，作 如果，那么”講。詳解例句 如果主句用的是一般將來時(shí)，I will visit my gr

2、a ndmother if I am free.if 引導(dǎo)的條件狀語從句常用一般現(xiàn)在時(shí)。Let' go shopp ing if you are not busy. 如果主句是祈使句，從句也常用一般現(xiàn)在時(shí)。You must be careful if you goswimming in the river. 如果主句含有情態(tài)動詞，從句一般也用一般現(xiàn)在時(shí)。if 引導(dǎo)的條件狀語從句可以放在If you don ' hurry, you will be late. =You主句前面，常用逗號隔開；也可以放在主句的后will be late if you don' hurry.

3、面。精品資料祈使句 +and (or)+ 陳述句 " 在Hurry up, or you' be late.意義上相當(dāng)于一個(gè)含有條件狀語從句的復(fù)=If you don' hurry up, you' be late.合句。轉(zhuǎn)換if+否疋句相當(dāng)于unless+ 肯Don ' come in if I don ' call you.定句”=Don ' come in unless I call you.注：當(dāng)連詞if 作 是否”講時(shí)， if 引導(dǎo)的從句的時(shí)態(tài)要根據(jù)具體情況而定。()1. I hear Jack Chan will come

4、to Laiwu next week.( 2010 山東萊蕪 )Really? _ he comes, my youn ger sister will be very happy.A. IfB. Un til C. Uni ess D. Before()2. I don 'tknow if it _tomorrow. If it _ , we won ' go on a picnic.A. rains; rai ns B. will rain; rai ns C. will rain; will rain()3. We will have no water to drink_

5、we don ' protect the earth.( 2010 上海 )A. un tilB. beforeC. thoughD. if【鞏固練習(xí)】I 單項(xiàng)選擇()1. We will stay at home if my aunt_ to visit us tomorrow.A. comeB. comesC. will come D. is coming精品資料( ) 2. Do you know if he_ to play basketball with us? I think he will come if he_ free tomorrow.A. comes; is B.

6、 comes; will beC. will come; is D. will come; will be( ) 3. You will keep healthy _ you do more exercise, such as running and swimming.A. ifB. howC. before D. wheren.根據(jù)漢語意思完成下列句子，每空一詞。4. 如果明天不下雨的話，我們將去動物園。We will go to the zoo_ tomorrow.5. 如果你完成了作業(yè)，我們就去下象棋。_ , let ' s go to play chess.6. 如果人人都能保

7、護(hù)環(huán)境，世界將會變得更美好。If everyone protects the environment, the world _ .二、非真實(shí)條件句: 也叫虛擬條件句，表示與現(xiàn)實(shí)情況相反的假設(shè)情況。主句和從句中的謂語動詞都需要使用虛擬語氣。在表示與事實(shí)相反的虛擬語氣時(shí)，謂語動詞有三種形式。體其具、形式如下：時(shí)間概念條件從句中的謂語動詞主句中的謂語動詞與現(xiàn)在事實(shí)相反did/werewould(could/should/ might)+do與過去事實(shí)相反had done/beenwould(could/should/might)+have done與將來事實(shí)相反did/werewould(could

8、/should/ might)+ doshould do精品資料were to do注意： 1.上述主句的謂語中,would 表示結(jié)果， might 表示可能性， could 表示能力、允許或可能性， should 主要用于第一人稱后。2. 條件從句的謂語動詞為be 時(shí)，不管其主語是單數(shù)還是復(fù)數(shù)通常用were 。例如：If he were here now, we could ask him about it.（與現(xiàn)在事實(shí)相反）3. 混合條件句。當(dāng)條件狀語從句表示的行為與主句表示的行為所發(fā)生的時(shí)間不一致時(shí)，動詞的形式要根據(jù)它所表示的時(shí)間做出相應(yīng)的調(diào)整。例如：If he had followed

9、 the doctor'advice the n, he would be quite all right now.（從句表示過去時(shí)間，主句表示現(xiàn)在時(shí)間）4. （省 if ）倒裝的虛擬條件句。虛擬條件句的從句部分如果含有were, should或 had, 可將if 省略，把 were, should或 had 移到從句主語前形成倒裝。例如：Had I seen him the n, I would have bee n very happy.5. If it weren ' for和 If it hadn ' been for 是兩個(gè)很常用的虛擬語氣句型，其意為若不是

10、（有），要不是有”。前者談?wù)摤F(xiàn)在的情況，后者談?wù)撨^去的情況。【即學(xué)即練】一、用動詞的適當(dāng)形式填空。1. What will you do if it_（ rain ） tomorrow? We have to carry it on, since we 've got everyth ing ready.精品資料2.She told me that she would not go with me if it_ （rain ） the n ext day.3.If I _ (be) you, I would plant some trees round the house.4.If I

11、 had been you then, I _ (not quarrel) with him.5.If the United States had built more homes for poor people in 1955， the housingproblems now in some parts of this country_ (not be) so serious.二、選擇填空1. John went to the hospital alone. If he _me about it, I would have gone with him.A. should tell B. te

12、llsC. told D. had told2. If we _the other road, we might have arrived here in time for the meeting.A. take B. had takenC. took D. have taken3. If he _my advice, he wouldn' t have lost his job.A. followed B. should followC. had followed D. would follow4. Had I known about this computer program, a

13、 huge amount of time and energyA. would have been saved精品資料B. had been savedC. will be savedD. was saved5._for the free tickets, I would not have gone to the films so often.A. If it is not B. Were it notC. Had it not been D. If they were not6. The weather has been very hot and dry. Yes. If it had rained even a drop, things would be much better now! And my vegetables _A. wouldn ' tdie B. didn ' tdieC. hadn ' t died D. wouldn' t have died一、【中考鏈接】1-3 ABD【鞏固練習(xí)】1-3 BCA4. if it doesn'