情态动词和虚拟语气重点与难点

情态动词和虚拟语气

情态动词

（一）表示推测的情态动词

对现在或将来情况推测，用情态动词+do / be / be doing…；对过去的推测，用情态动词+have done / been…；表示肯定推测的情态动词must, should / ought to, may, might, 否定推测，常用can’t / couldn’t，译为“根本不可能”、“想必不会”，表示推测的语气非常肯定，may not, might not译为“可能不”、“也许不”，表示推测的语气不很肯定。

(1) must表示推测，意为“一定……”，只能用于肯定句中。must have done意为：一定做过某事或某事肯定发生了。例如：

(NMET2007 江苏)—She looks very happy. She ______ have passed the exam.

—I guess so. It’s not difficult after all.

A. should

B. could

C. must

D. might

【解析】句意为：她看上去很高兴，一定是通过了考试。

【答案】C

(2) should (not) / ought (not) to在中表示根据常规或常识推测，表示“某事应该或不应该发生”。例如：(NMET2007全国I)—How’s your tour around the North Lake? Is it beautiful?

—It ________ be, but it is now heavily polluted.

A. will

B. would

C. should

D. must

【解析】should此处表示推测，意为“应该”。

【答案】C

②(NMET2005上海)There _________ be any difficulty about passing the road test since you have practiced a lot in the driving school.

A. mustn’t

B. shan’t

C. shouldn’t

D. needn’t

【解析】句意：既然你在驾校进行了大量训练，那么通过道路测试按理不应该有困难。

【答案】C

(3) can, could表达推测时，一般用于疑问句和否定句中；can用于肯定句中表示一种理论上的可能性，并不牵涉是否真的会发生，在这种用法中can只能与动词原形连用

例如：

①（NMET2008浙江）You ______ be hungry already — you had lunch only two hours ago!

A. wouldn’t

B. can’t

C. mustn’t

D. needn’t

②（NMET2008天津）She ______ have left school, for her bike is still here.

A. can’t

B. wouldn’t

C. shouldn’t

D. needn’t

③（NMET2008福建）It is usually warm in my hometown in March, but it _____ be rather cold sometimes.

A. must

B. can

C. should

D. would

④（NMET2008辽宁）Peter ____ be really difficult at times even though he’s a nice person in general.

A. shall

B. should

C. can

D. must

【解析】①②两个考题中can用于表示否定的推测，意为：不可能，一定不会；③④两个考题中can表示理论上的可能性，翻译为：有时候会……。

【答案】① B ② A ③ B ④ C

(4)may (not) / might (not)表达一种不太把握的推测，意为“或许，可能”

例如：

① (NMET2008全国II) Liza ___ well not want to go on the trip --- she hates traveling.

A. will

B. can

C. must

D. may

【解析】may well为固定搭配，意为：很可能，极有可能。

【答案】Ｄ

② (NMET2008四川) Although this ____ sound like a simple task, great care is needed.

A. must

B. may

C. shall

D. should

【解析】这听起来或许是一项简单的任务，但却需要极大的细心。

【答案】B

③ (NMET2008重庆)—I can’t find my purse anywhere.

—You __ have lost it while shopping.

A. may

B. can

C. should

D. would

【解析】结合语境可知，回答者是在提醒对方：或许购物时把钱包丢了。

【答案】A

（二）表达虚拟语气的情态动词

对过去的一种结果的假设或虚拟，用情态动词+have done这一结构，常用的有以下几个情态动词：(1) should (not) / ought (not) to have done本（不）应该做某事，但却没有做或做了，含有责备或后悔之意。例如：

（NMET2008江苏）—I’m sorry. I _________at you the other day.

—Forget it. I was a bit out of control myself.

A. shouldn’t shout

B. shouldn’t have shouted

C. mustn’t shout C. mustn’t have shouted

【解析】对不起，我那天本不应该对你大喊大叫的。

【答案】B

(2) could have done本来能够做某事但未做。例如：

（NMET2008山东）Thank you for all your hard work last week. I don’t think we ______ it without you.

A. can manage

B. could have managed

C. could manage

D. can have managed

【解析】根据题干中所给出的时间last week可知我们已经做完了工作，已经完成，故排除A、C 两项，再结合could have done表示虚拟语气以及与前面的I don’t think…，故说话者想表达的意思是：离开了你，我们本不可能完成这项工作。

【答案】B

(3) needn’t have done本没有必要做某事但却做了。要注意needn’t do则表达“没有必要去做某事”，时间上应该是现在或将来。例如：

①(NMET2005福建)—Catherine, I have cleaned the room for you.