亲爱的同学们,今天进入谓语的另一部分,情态,情态的表达是通过情态动词来表达的,所以今天主要来讲情态动词,情态动词是一种本身有一定的词义,但要与动词原形及其被动语态一起使用,给谓语动词增添情态色彩,表示说话人对有关行为或事物的态度和看法,认为其可能、应该或必要等。情态动词后面加动词原形。
分类
情态动词有五类:
①只做情态动词:must,can(could),may(might),,ought to
②可做情态动词又可做实意动词:need,dare
③可做情态动词又可做助动词:shall(should),will(would)
④具有情态动词特征:have(had,has) to,used to
⑤情态动词表猜测
位置
情态动词有一定的词义,但并不完整,必须与动词原形一起构成谓语。
I can see you. Come here.
我能看见你,过来吧。
He must have been away.
他一定走了。
What can I do for you?
我能帮你吗?
How dare you treat us like that!
你怎能那样对待我们!
特点
情态动词无人称和数的变化, 情态动词后面跟的动词需用原形,否定式构成是在情态动词后面加 "not"。 个别情态动词有现在式和过去式两种形式, 过去式用来表达更加客气, 委婉的语气, 时态性不强, 可用于过去,现在或将来。情态动词属非及物动词,故没有被动语态。
He could be here soon.
他很快就来。
We can't carry the heavy box.
我们搬不动那箱子。
I'm sorry I can't help you.
对不起,我帮不上你。
除此之外,情态助动词还有如下词法和句法特征:
1) 除ought和used以外,其他情态动词后面只能接不带to的不定式。如果我们把ought to和used to看做是固定词组的话,那么,所有情态动词无一例外地只能接不带to的不定式:
We used to grow beautiful roses.
I asked if he would come and repair my television set.
2) 情态助动词在限定动词词组总是位居第一:
They need not have been punished so severely.
3) 情态助动词用于第三人称单数现在时的时候,没有词形变化,即其词尾无-s形式:
She dare not say what she thinks.
4) 情态动词没有非限定形式,即没有不定式和分词形式,也没有相应的 动名词:
Still, she needn't have run away.
5) 情态助动词的“时”的形式并不是时间区别的主要标志。在不少场合,情态助动词的现在时和过去时形式都可以表示现在、过去或将来时间:
Would you mind very much if I ask you to do something?
She told him he ought not to have done it.
6) 情态助动词之间是相互排斥的,即在一个限定动词词组中只能出现一个情态助动词,但有时却可以与have和be基本助动词连用:
You should have washed the wound.
Well, you shouldn't be reading a novel.
好了,感觉又有点儿多了哈,明天来看看具体的情态动词的具体用法哦,亲爱的孩子们。。。
1. We __________ have proved great adventurers, but we have done the greatest march ever made in the past ten years.
A. needn’t B. may not
C. shouldn’t D. mustn’t
2. Some aspects of a pilot’s job __________ be boring, and pilots often __________ work at inconvenient hours.
A. can; have to B. may; can
C. have to; may D. ought to; must
本帖隐藏的内容
答案:B。比较:needn’t have done意为“本来不必做某事”,may not have done意为“(过去)可能没有做某事”,shouldn’t have done意为“本来不应该做某事”(must表推测时不用于否定式)。根据句意,显然只能选B。