2015年在职工硕英语备考：一般情态动词

　　1、情态动词的完成式：

　　⑴ 情态动词的完成式即"情态动词+ have + v-ed分词"，表示对过去行为或动作进行推测、评论或判断。如：

　　Since the ditch is full of water, it must have rained last night. 沟渠里的水都满了，想必昨晚一定下雨了。

　　You couldn't have met my grandmother. She died before you were born.你不可能遇到我奶奶，因为她早在你出生前就死了。

　　I can't find my keys. I may / might have left them at the school yesterday.我找不到钥匙了，也许昨天丢到学校了吧。

　　⑵ 当情态动词完成式是由ought to / should加完成式或否定式ought not to / shouldn't加完成式时，是表示对已发生的情况表示"责备"、"不满"，分别表示"本应该…"和"本不应该…"。例如：

　　You ought not to make fun of him. He is not the one you laugh at but learn from.你本不应该取笑他的。他不是你嘲笑是热恰恰是你应该学习的一个人。

　　You should have finished your composition by yesterday.你本应该昨天前就把作文写完的。

　　⑶ needn't have v-ed

　　needn't have v-ed 表示过去做了某事，但没有做的必要， 意为"本没必要…"。例如：

　　You needn't have wakened me up; I don't have to go to work today.你本没必要把我叫醒，因为我今天不上班。

　　注：表示推测过去某动作发生的可能性时，就表示的可能性程度而言，must最大，could其次，may更次之，might最小。

　　重要考点

　　1 情态动词+have+done

　　Must do/must have done 肯定句中表肯定推测(90%)

　　Can/could not do /haven done否定句中表推测(表示不可能)

　　Should have done 本该做却没做

　　Shouldn't have done本不该做却做了

　　Needn't have done没必要做却做了

　　Could have done本可以做却没做

　　Wouldn't have done sth本来不会(虚拟)

　　Would have done sth本来会(虚拟)

　　I could have arrived a little earlier, but I met a friend of mine on the way.

　　The children must have got terrified in last night's earthquake.

　　You should have put the milk in the ice-box; I expect it had become undrinkable by now.

　　You needn't have told her again because she has a good memory.

　　Let's go to class together, shall we?

　　2、情态动词的进行式

　　情态动词+行为动词进行式(即情态动词+ be + v-ing形式)，表示推测或评论某动作现在是否正在进行(应当正在….、想必/一定正在…、可能/也许正在..;)。例如：

　　The light in his study is still on; he must be working now.他书房的灯还亮着，想必他现在还在工作。

　　She shouldn't be working like that. She is still very weak.她不应该这样干,她身体还这样弱.

　　He can't be telling the truth. 他说的不可能是真话.

　　3、情态动词的完成进行式

　　情态动词+行为动词完成进行式(即情态动词+ have been + v-ing 形式)，表示推测或评论过去某动作是否正在进行或一直在进行。例如：

　　They are sweating all over. They must have been working in the fields.他们浑身是汗，准是在地里一直干活来着。

　　They may have been discussing this suggestion all the morning.今天上午他们可能一直在讨论这个建议来着。

　　He shouldn't be watching TV now. It's time for class. 他不该在看电视，该上课了。

　　He said he could drink a bottle of whisky. He must be joking.他说可以喝一瓶whisky,他一定在开玩笑。

　　The president of our company isn't here. He may be interviewing candidates for the post of sales manager at the moment.公司总裁不在。他这会儿可能正在面试销售经理的应聘者。

　　They must have been working on their thesis.他们一定一直在写论文。

  本文选自新东方在线论坛。