第九讲 情态动词和虚拟语气一、情态动词考点透析 (could)，be able to。 只有现在式can和过去式could两种形式可用于现在式、过去式、将来时、完成时。要表示“能够做某事”可用can或be able to但若要说过去的确运用了某种能力做成了某件事情就只能用was/were able to表将来具备的能力只能用will/shall be able to。(1)If you study hard，you will be able to express freely in English in three months.
如果你努力学习三个月后你就能自由地用英语表达了。(2)The fire spread through the hotel very quickly but everyone was able to get out.
大火迅速在酒店蔓延但每个人最终还是逃出去了。是can的过去式但是在很多情况下特别是在口语中它表示语气的委could提问时不能用could回答而要用can或may。would用于疑问句时也表委婉语气回答时应该用will。(1)－Could I borrow your dictionary?能借用一下你的词典吗？－Yesurse you can.
——可以当然可以。(2)－Could I call you by the first name?我可以直呼你的名字吗？－Yes行可以的。(3)－Would you be so kind as to explain the word?请你好心地解释一下这个字好吗？－Yes好的哪个字？都可表示可能但may/might 不能用于问句用于否定句、疑问句、感叹句表示惊异、怀疑一般不用于肯定句。如果用于肯定句则表示偶尔发生某事的可能或某人某物一时的特点。(1)－Are you coming to Jeff's party?I'm not sure.I might go to the concert instead.
——说不好我可能会去音乐会。(2)－Where can Mr.Li be?李先生会在哪里呢？－Sorrycan go to ask Mr.Zhang.He may help you.
——对不起我不知道。你可以去问问张先生他可能会帮到你。(3)Mr.Bush is on time for everything.How can it be that he was late for the opening ceremony?
布什先生做什么都准时开幕式时他怎么就迟到了呢？(4)We enjoy good weather in January，but sometimes it can be terribly cold.
我们这儿一月份天气都很好但是偶尔也会很冷的。表推测用于肯定句其否定式要用can't。对现在表示推测：；can't do对正must be doing；can't be doing对过去表示推测：；can't/couldn't have done(1)－There were already five people in the car车里已经有五人了但他们还是设法带上了我。－It couldn't have been a comfortable journey.2)Jack can't have arrived yet，otherwise he would have telephoned me.
杰克不可能已经到了否则他会给我电话的。(3)Put on more clothes，you must be feeling cold with only a shirt on.
多穿点衣服只穿一件衬衣你一定觉得冷吧。(4)I didn't hear the phone.I must have been asleep.
我没有听5．情态动词完成式的意义。过去可能做过过去本来可以做某事但没有做过去一定做过可能已经做过本来可以做但没做 have done过去可能做过过去本来可以做但没做过去不可能做过某事(not) have done
过去本该(不该)做但却没做ought (not) to have done
过去本该(不该)做但却没做(做了)过去本来没必要做但却做了(not) have done宁愿过去做了(没做)注意：must have done都表推测。其区别在于可能性的大小。must have done表很有可能表有可能表可能性很小则为“不可能”。(1)I told Sally how to get here，but perhaps I should have written it out for her.
我告诉过莎莉怎么来这儿不过也许我该写给她的。(2)Sorry，I'm late.I might have turned off the alarm clock and gone back to sleep again.
对不起我迟到了。我可3)I was really anxious about you.You shouldn't have left home without a word.
我真为你担心你不该什么也不说就离家出走的。(4)Tom needn't have got up that early since it was Sunday and he had nothing important to do.
汤姆本来没有必要起那么早的因为是星期天他也没什么重要事情。(5)I would rather not have blamed him because he was a child after all.
我宁愿没有责备他。因为他毕竟只是个孩子。关于should的主要用法。(1)It's already seven o'clock.Jack should be here at any moment.
已经七点钟了杰克随时都可能来的。(should表推测意为“随时都会来”真该来了”)(2)－When can I come for the photos? I need them tomorrow afternoon.我什么时候来拿照片？我明天下午要用。－They should be ready by 12：00.(should：应该)十二点前应该就可以了。(3)You can't imagine that a wellbehaved gentleman should be so rude to a lady.
你难以想象一个举止优雅的绅士对女士居然这么粗鲁。(should表惊异意为“居然”、“竟然”)(4)If he should fail to come，ask Mr.Zhang to attend the ceremony instead.
要是他万一来不成就叫张先生代替出席这个典礼吧。(should表语气较强的假设意为“万一”)(5)We should have studied last night，but we went to the concert instead.(should have studied：我们本该学习的但却没有学习)我们昨晚本该学习的但是我们却去了音乐会。关于shall的用法。用于第一人称、第三人称疑问句中表示说话人征求对方意见或向对方请示。用于第二、第三人称表示说话人给对方的命令、警告、允诺或威胁。(1)Shall I go on reading the text?
我要继续读课文吗？(shall：征求意见)(2)You shall be punished one day for what you've done.
总有一天你会因你的所作所为受到惩罚的。(shall：威胁警告)3)He shall get what he deserves.I promise it.
他会得到他应该得到的我保证。(shall：允诺)
按照句子结构的语法性和句子连贯的要求在空白处填上适当的情态动词或根据提示使用正确形式的情态动词。________ (not) use a clock to wake me up because at six o'clock each morning the train comes by my house.
2．I________ (not) thank you too much for all your help to my son while we were away from home.
3．—________ you interrupt now? Can't you see I'm on the phone?
—Sorry Sir, but it's urgent.
4．I got close enough to hear them speaking Chinese, and I said “Ni Hao” just as I ________do in China.
5．We ________ (not) have bought so much food now that Suzie won't be with us for dinner.
6．One of our rules is that every student________wear school uniform while at school.
7．I'm going to Europe on vacation together with John if I ________ find the money.
8．—You have to believe in yourself.No one else will, if you don't.
—I ________ (not) agree more.Confidence is really important.
9．The new law states that people ______(not) drive after drinking alcohol.
10．It's quite warm here; we ________(not) turn the heating on yet.
11．—No one ________ be compared with Yao Ming in playing basketball.
—Oh, you are really his big fan.
12．The police still haven't found the lost child, but they're doing all they ________．________ (not) be the postman at the door.It's only six o'clock.
14．—How's your new babysitter?
—We ________ (not) ask for a better one.All our kids love her so much.
15．—I don't really like James.Why did you invite him?
—Don't worry.He ________ not come.He said he wasn't certain what his plans were.
16．If you
________ smoke, please go outside.
17．If you ______ go, at least wait until the storm is over.
18．—Shall I inform him of the change of the schedule right now?
—I am afraid you ________， in case he comes late for the meeting.
19．I ________ (not) worry about my weekend.I always have my plans ready before it comes.
20．—Will you read me a story, Mummy?
—OK.You________ have one if you go to bed as soon as possible.
答案： 2.can't 3.Must 4.might 5.needn't 7.can 8.couldn't/can't 9.mustn't 10.needn't 11.can 12.can 13.can't 14.couldn't 15.might 16.must 17.must 18.must 19.needn't 20.shall二、虚拟语气考点透析虚拟语气在非真实条件句中的用法。
时间 if从句动词 主句动词
与现在事实相反 did(be改为were) should/would/could/might＋do与过去事实相反 had＋done
should/would/could/＋have done
与将来事实可能相反 did/should do/were to do should/would/could/might do如：(1)If she were here，everything would be all right.(But she isn't here now.)
如果她在这儿一切就好办了。
(2)If you had come five minutes earlier，you would have met the famous pop singer.
如果你早来五分钟你就可以看见那个著名的流行歌手了。(3)If it were to rain tomorrow，the outing would be canceled.
要是明天下雨的话郊游就要取消了。(4)If you should visit our school tomorrow，you would see how beautiful it is.
如果你明天来参观我们学校的话你就会发现它有多美！
＋宾语从句 (宾语从句
时间 动词形式 例句
与现在事实相反的愿望 did(be改为were) I wish I were ten years younger.我希望年轻十岁。
与过去事实相反的愿望 had＋过去分词 He wishes he had gone to the concert last night.他希望
将来难以实现的愿望 should/would/＋动词原形 The last chance has been lost.How he wishes he could have another chance.最后的机会已经失去了他多么希望能再有一次机会。3.在非真实条件状语从句中如果含有were可将if省去将were放在主语前构成倒装。如：(1)What would have happened had Bob walked farther，as far as the river bank?
要是鲍勃走得更远些一直走到河堤上的话会发生什么呢？(2)Should I fail this time，I would wait for another chance.
万一我这次失败了我会等待下次机会的。在非真实条件状语从句中有时条件从句与主句动作发生的时间是不一致的这时动词的形式要根据动词所表示的时间(1)If you had worked harder，you wouldn't be afraid of the examination now.
如果你早点努力的话现在你就不会害怕考试了。(2)If he had followed the doctor's advice，he would be quite all right now.
如果他早听了医生的话他现在就好了。有时假设的情况并不or，otherwise，with，without，but for(要不是)等词经常出现在含蓄虚拟条件句中。如：(1)He hesitated for a moment before kicking the ball，otherwise he would have scored a goal.
在起脚射门时他犹豫了一下否则他就进球了。(2)Without electricity human life would be quite different today.
如果没有电人类今天的生活就会完全不同。(3)Under more favorable conditions，the rice would grow much better.
如果条件更有利的话水稻会长得更好。(4)But for your help，I would still be working in the lab now.
要不是有你帮忙我现在还在实验室埋头苦干呢。情态动词的完7．在下列句型中动词要用虚拟语气： if it were not for要不是因为……要不是因为……要是……就好了！(表强烈愿望)(1)If only he were here!
要是他在这就好了！(2)If it had not been for the snow，we could have climbed the mountain yesterday.
要不3)If only he had lain quietly as the doctor instructed，he would not suffer so much now.
要是他能像医生嘱咐的那样安静地躺着的话现在他就不会受这么多罪了。后的从句中动词要用虚拟语气。如表示与现在的情形相反动词用过去式；如表示与过去的情形相反动词用had＋过去分词。如：(1)Tom is com ing soon，but I would rather he came tomorrow.
汤姆很快就到了可我宁愿他明天再来。(2)Jane is crying sadly.I would rather you hadn't told her the bad news.
珍妮在伤心流泪呢我宁愿你没有把那坏消息告诉她。
Ⅰ.用所给动词的适当形式填空。________(book)a table earlier，we wouldn't be standing here in a queue.
2.If he had spent more time practicing speaking English before，he________(be) able to speak it much better now.
3．－It rained cats and dogs this morning.I'm glad we took an umbrella.－Yeah________(not take) one.
4．Eye doctors recommend that a child's first eye exam________(be) at the age of six months old.
5．I should not have laughed if I________(think)you were serious.
6．Sorry, I am too busy now.If I ______ (have) time, I would certainly go for an outing with you.
7．We lost our way in that small village, otherwise we ________(visit) more places of interest yesterday.
8．If my car __________(be) more reliable, I would have driven to Lhasa instead of flying last summer.
9．Had they known what was coming next, they________ (have) second thoughts.
10．Jack is a great talker.It's high time that he ________(do) something instead of just talking.
11．We ________(face) the difficulty together, but why didn't you tell me?
12．Don't handle the vase as if it ________(be) made of steel.
13．We would have called a taxi yesterday if Harold ____________(not offer) us a ride home.
14．I____________(go) through that bitter period without your generous help.
15．—Where are the children? The dinner's going to be completely ruined.
—I wish they ________ (be not) always late.
16．If it________(be not) for your help，I could not have entered this famous university.
17．I would rather I________(not grow) up so that I would not worry about such a thing.
18．It is high time that we________(take)action to protect wildlife.
19．My mom suggests that we________(eat)out for a change this weekend.
20．If we________(take)the other road，we might have arrived here in time this morning for the meeting.
Ⅱ.用所给动词的适当形式填空。Tom and Peter are twins. They look as if they 1.______ (be) the same person. Both the two boys are smart, but Tom is hardworking while Peter is lazy. Tom always wins the first place in the exams while Peter doesn't.However, people believe if Peter 2.______ (work) as hard as Tom，he would do as well as his brother in his study.
At home, their parents suggests that they 3.______(finish) their homework before playing computer games. But Peter insists that it 4.______ (be) OK to play games first as long as he can hand in his homework in time. Their mother gives in in the end.
One day, when doing his homework, Tom found he made a serious mistake. So he put his exercise book aside and used another one. When Peter found the previous exercise book, he struck out Tom's name and signed his name on its cover happily, and handed it in as his own homework the next day.
When the teacher told the truth to the twins' mother, she was very angry and shouted at Peter, “How I wish you 5.______ (be) as diligent as your brother! Now it's time that I 6.____ (give) you a good lesson. And you 7.______ play any computer games for a month！” Mom. Without a computer for such a long time, I 8.______ (die). I would rather you 9.______ (ask) me to do the dishes for a month alone.”Peter was upset.
“If you 10.________ (finish) your homework on time yesterday, you wouldn't be punished now，”said the mother.
答案： 2.would be 3.hadn't taken(should)be 5.had thought 6.had 7.would have visited 8.had been 9.might have had 10.did 12.were 13.hadn't offered 15.were not 16.were not 18.took 19.(should) eat 2.worked 3.(should) finish 4.is 6.gave/should give 7.mustn't 8.would die 10.had finished