2015年GCT工程硕士英语考试词汇语法指导（46）
发布时间：2009/11/20 14:42:08 来源：城市学习网 编辑：紫藤
1、情态动词后面加不定式的完成式，即“情态动词+ have + done”，用来表示过去时间的各种情态。用法如下：
用在句子中，对过去的行为或过去的行为或动作的推测、评论或判断，表示某种事情“一定”“可能”或“应该”已经完成或发生了。考生应该牢记不同的情态动词与不定式完成式连用所表达的意思。如：wouldn’t have done sth （本来不会…）should/ought to have done sth.（本应/应该已经…），shouldn’t/oughtn’t to have done sth.(本不该…)，would have done sth （本来会…）can/could/may/might have done sth.(可能已经/也许已经…)，must have done sth.(一定/准时/准是…)，can’t/couldn’t have done sth.(一定没/准没有…)。Needn’t + 完成式表示对已经做过的事感到是不必要的。
例：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.
Since they aren’t answering the telephone, they must have left.
You needn’t have told her again because she has a good memory.
You needn’t have interrupted the class to tell me that; you could have come up to me afterwards.
2、情态动词后面加进行时，即“情态动词 + be + doing”，表示“应当正在…”、“想必/一定正在…”、“可能/也许正在…”等意思。情态动词后面加上完成进行式，即“情态动词 + have been doing”，表示“应当一直在…”、“想必一直在…”等意思。
例：He shouldn’t be watching TV now. It’s time for class.
The president of our company isn’t here. He may be interviewing candidates for the post of sales manager at the moment.
The economy seems to be sluggish these days.
He said he could drink a bottle of whisky. He must be joking.
They must haven been working on their thesis.
3、情态动词后面的被动语态。在很多情况下，动词的主语是动作的承担者，因此，是有情态动词的句子，情态动词后面就要跟动词的被动语态形式。
例：The Central Park can be seen from the top of this exclusive apartment building.
Many rare animals should be saved from extinction.
The girl must have been frightened by the thrilling movie in which there are some violent scenes.
