EST(六.虚拟语气).ppt

1、六虚拟语气 语气：用动词形式的变化来表示说话的人对自己说的话所持的看法和态度，叫做语气. 语气分为三种： 陈述语气：陈述事实，如: You are very careful. 祈使语气：提出请求，命令等，如： Please be careful. Be quielt. 虚拟：表示说话人认为自己所说的话不过是一种主观愿望或设想，或与事实相反，或不能实现，或实现可能性不大。虚拟语气有其特有的一套动词形式. I wish I were in Beijing now. 我现在要在北京就好了.（与事实相反的愿望） If air were a good conductor of heat,we shoul

2、d be burned. 若空气是热的良导体，我们就会被烧死。,虚拟语气在虚拟条件句中的应用. 条件从句有两种，其一是真实条件句，即说话人认为假设的条件是真实的或完全可能发生的，其谓语动词用陈述语气，如： If air is passed through a drying agent the moisture will be removed. 若使空气通过干燥剂，其水分就会被除去。 若说话人认为自己假设的条件不符合事实或将来实现的可能性很小，因而相应的推测或结果也是不真实的，这种从句就叫虚拟条件句，就得用虚拟语气.这有三种基本情况： 假定的条件与现在的事实相反，则条件句中谓语动词用过去时（be

3、全用were）,主句中谓语动词用should,would,could,+动词原形. If he had time,he would help you. If I knew English,I should be able to read these English books. If there were no gravity,there would be no air around the earth. What would take place if there were no friction in the brakes of a tractor?,.假定的条件与过去事实相反，则条件句中

4、谓语动词用过去完成时，主句中谓语动词用should,would,could,+现在完成时. If the friction had not been great,the pump would not have been damaged. If you had come here yesterday,you would have seen him. If we had known the basic principles,we should have controlled the process even better.,.与将来事实可能相反（不可能实现或可能性较小）的假设，则条件句中谓语动词用

5、should,could,，might ,were to +动词原形，主句则为should,would,could+动词原形. If all the ice in the North Pole were to melt,the sea level all over the world would go up many meters higher. If she should come to us,she would answer these questions. (假如她真能来我们这里的话，她会回答这些问题的).事实上她来的可能性较小，或者不存在. 现将以上三种情形列表示之：,2.主谓倒装的形

6、式表示虚拟条件：若条件从句中谓语有were,had,should时，则省去if,把它们提前，形成倒装： Were there no no gravity,there would be no air around the earth.= If there were no gravity,there would be no air around the earth. Were she in Tientsin,she would help us.= If she were in Tientsin,she would help us. Should they come to us,I should a

7、sk them some questions.= If they should come to us,I should ask them some questions. Had the checking up of the experimental data not taken so much time,we should have completed our work long ago.= If the checking up of the experimental data had not taken so much time,we should have completed our wo

8、rk long ago. Had there been no electronic computers,there would not have been artificial satellites or rockets.=If there had been no electronic computers,there would not have been artificial satellites or rockets.,虚拟语气有两个明显特点：1）自成一体，不符合有关人称、数和时态的一般语法规则（如所有人称单、复数都用were,用动词过去时表示与现在相反的假设等）；2）should,wou

9、ld 用得较多。因此，判断是否是虚拟语气，通常可以从主从句时态的呼应、上下文的时态，以及这几种时态本身的用法，并结合句子内容来加以考虑，如： People might have avoided many accidents if ultrasonic methods had been known before. (假如人们以前就知道超声方法的话，许多事故或许就不会发生了) 这里的“had been known”既可以是陈述语气的过去完成时，也可能是表示与过去事实相反假设的虚拟语气，但主句谓语为“might have avoided”，正好与所作的假设和过去事实相反时，相应的主句谓语的虚拟语气形

10、式的规则相符。因此可以肯定，had been known 是虚拟语气，而不是陈述语气的过去完成时。又如： Being on the moon would be very difficult because there is no oxygen or water. In fact there is no atmosphere of any kind. (在月球上想必是非常困难的，因为那里没有氧气，没有水，而且事实上没有任何种类的大气),这里的“would be”既可以是虚拟语气，也可能是过去将来时，这里并没有表示假设的条件从句。但because 引导的原因状语从句的谓语is ，以及后面一个句子的

11、谓语is,都是一般现在时，不可能表示某一特定时刻，这就使would be 失去了作过去将来时的依据，因此，依上下文时态判断，would be 是虚拟语气。,Exercise 一、单项填空，在A、B、C、D四个答案中，选出可以填入空白处的正确答案。 1.If I-you ,I wouldnt return the call. a. be b. am c. was d. were 2. I would have gone to ,the meeting ,if I-time. a. had had b. have had c. had d. wold have had 3. If you had

12、been with us, you-our excitement. a. have understood b. understood c. will understand d. would have understood 4.-today, he would get there by Friday. a. Would he leave b. Was he leaving c. Were he to leave d. If he leaves 5. I didnt know this Picasso exhibit was closed, but I wouldnt have been to c

13、ome even if -about it. a. I know b. Id known c. I have been knowing d. Ive known,6. If I had time,-see that new movies at the University Theater. a. Ill be b. I shall c. I may d. Id 7. Without your help, we- so much. a. will not achieve b. didnt achieve c. dont achieve d. would not have achieved 8. -,Id have told you. a. If I would have known it, b. If I