if引導的虛擬語氣（課堂PPT）

1、1真實條件句和真實條件句和虛擬條件句虛擬條件句231.表示客觀事實或真理表示客觀事實或真理 If you freeze water, it turns to ice. If you eat a lot of chocolate, you put on weight. 真實條件句真實條件句 從句從句 主句主句 if+一般現(xiàn)在時，一般現(xiàn)在時一般現(xiàn)在時，一般現(xiàn)在時42.表示將來可能發(fā)生的事表示將來可能發(fā)生的事 If he fails in the exam, he will let his parents down. You will certainly succeed if you keep on

2、 trying. 從句從句 主句（陳述句）主句（陳述句） if+一般現(xiàn)在時，一般將來時（一般現(xiàn)在時，一般將來時（will+動詞原形）動詞原形）53.給某人提建議或命令某人做某事給某人提建議或命令某人做某事 If you feel sleepy, go to bed. If you want to know how it works, read the instructions. 從句從句 主句主句if+一般現(xiàn)在時，祈使句一般現(xiàn)在時，祈使句6If引導的虛擬條件句，即非真實條件引導的虛擬條件句，即非真實條件句，表示條件句所表示的條件根本句，表示條件句所表示的條件根本不可能實現(xiàn)或實現(xiàn)的可能性很小。不

3、可能實現(xiàn)或實現(xiàn)的可能性很小。根據(jù)動作發(fā)生時間的不同，含有非根據(jù)動作發(fā)生時間的不同，含有非真實條件句的復合句的主從句的謂真實條件句的復合句的主從句的謂語動詞采用不同的表達方式。具體語動詞采用不同的表達方式。具體分為三種情況：分為三種情況：虛擬條件句虛擬條件句7時間時間從句從句主句主句與與現(xiàn)在現(xiàn)在事實相反事實相反過去式過去式（be 通常用通常用were） should would could +動詞原形動詞原形 might與與過去過去事實相反事實相反 had+過去分詞過去分詞 should would could +have+過去分詞過去分詞 might與與將來將來事實相反事實相反過去式（過去式（

4、be 通常通常用用were）should+動詞原形動詞原形were to+動詞原形動詞原形 should would could +動詞原形動詞原形 might8一、與現(xiàn)在現(xiàn)在事實相反If I knew his telephone number, I would tell you .If I were you ,I wouldnt be so proud.9 二、與過去過去事實相反1.If he had taken my advice, he would not have made such a mistake.2.If I had got there earlier, I would hav

5、e met her.10 三、與將來將來的事實相反1.If there were a heavy snow next Sunday, we would not go skating.2.If she should come, I would tell her about the matter.11The printer is of good quality. If it _break down within the first year , we would repair it at our expense.A. would B. shouldC. couldD. might122._,the

6、 forest fire would have been discovered much earlier.A. But for their careB. If they were careful C. Without their careD. If they had been more careful134.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. wouldnt dieB. didnt dieC. hadnt diedD. wouldnt have died145.Had I known about the computer program, a huge amount of time and energy_.A. would have been savedB. had been savedC. will be savedD. was saved156.If we _ the ot