语法专练 情态动词和虚拟语气及巩固练习
常考点 | 必备点 |
①情态动词的基本用法；“情态动词＋have done”的用法；②虚拟语气用于非真实条件句中；③使用“(should)＋动词原形”结构的常用句型 | ①虚拟语气用于as if, if only后的从句中；②虚拟语气用于“would rather＋that”从句中；③虚拟语气用于含蓄条件句中、状语从句中 |
考点一 情态动词的基本用法
1 表能力
(1)表示现在的能力：can, am/is/are able to；
(2)表示将来的能力：will be able to；
(3)表示过去的能力：could表示过去的能力，不表示是否成功地做了；was/were able to表示过去有能力做而且成功地做了。
I'm going to Europe on vacation together with John if I can have enough money.
如果我有足够的钱，我将和约翰一起去欧洲度假。
2 表推测
(1)表肯定：can表示客观上的可能，意为“有时会”；may/might/could表示“可能”；must表示“一定”；should/ought to表示“应该”。
It is usually warm in my hometown in March, but it can be rather cold sometimes.
在我的家乡，三月份通常很暖和，但有时也会很冷。
(2)表否定：can't/couldn't表示“不可能”；may not/might not表示“可能不”；shouldn't/oughtn't to表示“应该不会”。
(3)表疑问：can/could表示惊讶、怀疑、不相信的态度。
3 表请求、建议、命令、允许、允诺、禁止、义务、责任
(1)请求对方允许时用“May/Can/Could I/we...？”；
(2)主动提出帮忙或提出建议时用“Shall I/we...？”；
(3)提出请求、问题、看法时用“Will/Would you...？”或“Shall he/she/they...？”；
(4)should/ought to表示“应该”，shouldn't/oughtn't to表示“不应该”；
(5)may/can表示允许、许可；
(6)must表示“必须”，mustn't表示“禁止”；
(7)shall与第二、三人称连用，用于陈述句，表示命令、警告、允诺、威胁；当宣布法律、规定时也常用shall。
One of our rules is that every student shall wear school uniform while at school.(规定)
我们的其中一项规定是学生在校期间必须穿校服。
4 表必要性
(1)must do sth表示主观上认为必须做某事；have to do sth表示因客观环境或事态促使而不得不做某事；
(2)needn't/don't have to表示“不必”。
You needn't get the machine repaired this week. I won't need it until next month.
这周你不必请人修理机器，我到下个月才用。
5 表意愿、决心
will/would可与各种人称连用，表示主语的意志或决心。will表示意愿时其否定形式为won't，通常用于有生命体，但有时也用于无生命体，这时是把无生命体拟人化了。
—Why hasn't the cook arrived yet today?
—She just won't come for such a low salary.
——为什么今天厨师还没来？
——这么低的薪水她不愿意来了。
考点二 情态动词的特殊用法
1 can/could的否定式与比较级连用表示最高级。
2 can/could的否定式与enough或too (much)连用表示“再……也不为过”。
I can't thank him too much.
我再怎么感谢他也不为过。
3 must可表示“偏要，硬要”，常用于疑问句或条件状语从句。
—Must you interrupt now? Can't you see I'm on the phone?
—Sorry, sir, but it's urgent.
——你非得现在打断我吗？你没看见我在打电话吗？
——对不起，先生，但我有急事。
4 may/might as well表示“最好；不妨”。
If you think the price of beef is too high, you may as well buy some pork.It depends on you.
如果你认为牛肉的价格太高，你不妨买些猪肉。这取决于你。
5 would可表示过去的习惯，与used to相比，前者常表示过去反复的动作，后者常表示过去的状态或习惯现在已不复存在。
He would get up early when he was in the country.
他住在乡下时总是早起。
6 should有时表示说话人对某事感到意外、惊奇，意为“竟然会”。
考点三 “情态动词＋have done”的2类用法
1 对过去发生的事情或状态进行推测
must have done | 表示“(过去)一定……”，语气比较肯定，用于肯定句。 |
may (might) have done | 表示“(过去)可能……”，语气不确定，用于肯定句或否定句。 |
can (could) have done | 表示怀疑或不确定，用于否定句或疑问句。 |
2 表示与过去事实相反
could have done | 过去本可以做某事但实际上没做 |
needn't have done | 过去本不必做某事但实际上做了 |
ought to/should have done | 过去本应该做某事但实际上没做 |
oughtn't to/shouldn't have done | 过去不应该做某事但实际上做了 |
might have done | 过去可能做某事但实际上没做 |
We could have faced the difficulty together, but why didn't you tell me?
我们本来可以一起面对困难，但是你为什么不告诉我？
Mark needn't have hurried. After driving at top speed, he arrived half an hour early.
马克本不必着急。他开得飞快，早到了半小时。
考点四 虚拟语气
1 虚拟语气用于条件句中的4种情况
(1)虚拟语气在if条件句中的运用
类别 | 从句谓语动词 | 主句谓语动词 |
与现在事 实相反 | 过去式(be用were) | should/would/could/might＋动词原形 |
与过去事实相反 | had＋过去分词 | should/would/could/might＋have＋过去分词 |
与将来事实相反 | 过去式(be用were) | should/would/could/might＋动词原形 |
| should＋动词原形 |
|
| were to＋动词原形 |
|
|
|
|
If he studied at this school, he would know the environment around the school very much.
如果他在这所学校学习的话，他会很了解周边环境。
(2)虚拟条件句中的省略与倒装
如果虚拟条件句中含有were/had/should，有时可把if省略，把were/had/should提到主语之前形成倒装；若为否定形式，not不可提前。
Had he caught the morning train, he would not have been late for the meeting.
要是他赶上了早晨的火车，那他开会就不会迟到了。
(3)错综时间条件句
有时条件句的动作与主句动作发生的时间不一致，这时动词的形式应根据它们各自发生的时间加以调整。
If we had booked a table earlier, we wouldn't bestanding here in a queue.(if条件句是对过去的虚拟，而主句是对现在的虚拟)
如果我们早些订位子，现在也就不用站在这里排队了。
(4)含蓄条件句
①有时假设的情况不用条件句表达，而是用but for, without等介词(短语)来表示。
We wouldn't have finished the project on time without your timely help.
如果没有你的及时帮助，我们就不能按时完成那个项目了。
②用连词otherwise, or等暗示后文与前面的情况相反，从而引出后文的虚拟语气。
③虚拟条件通过but暗示出来，模式为“虚拟情况＋but＋真实情况”。
2 虚拟语气用于名词性从句中的4种条件
(1)在“It is＋important/necessary/natural/strange/essential/vital/a pity＋that...”句型中，从句谓语动词用“(should＋)动词原形”。
It's vital that we (should) take our safety driving along the road seriously.
重视道路安全驾驶是至关重要的。
(2)在would rather (that)后的宾语从句中，从句的谓语动词如果表示现在或将来要发生的动作，从句用一般过去时；如果表示过去发生的动作，从句用过去完成时。
I'd rather he had gone to the seaside with me the day before yesterday.
要是他前天和我去海边就好了。
(3)句中含有以下单词或其变形时，该句中的名词性从句(宾语从句、表语从句、主语从句、同位语从句)部分常用虚拟语气，其谓语动词形式为“should＋动词原形”，其中should可以省略。
4)wish后的宾语从句中的虚拟语气
虚拟语气 | 从句谓语动词 |
与现在事实相反 | 过去式(be动词一般用were) |
与过去事实相反 | had＋过去分词 |
与将来事实相反 | would/could＋动词原形 |
3 3个特定句式中的虚拟语气
句型结构 | 过去虚拟 | 现在虚拟 | 将来虚拟 |
if only引导的条件句及感叹句 | had＋过去分词 | 过去式(be动词一般用were) | would/could/should/might＋动词原形 |
as if/though引导的表语从句及方式状语从句 | had＋过去分词 | 过去式(be动词一般用were) | would/could/should/might＋动词原形 |
It is (high) time (that)．.. | 过去式或“should＋动词原形” | ||
巩固练习
Ⅰ.单句语法填空
1．Sometimes chopsticks are quite artistic. Truly elegant chopsticks might be made(make) of gold and silver with Chinese characters.
2．If I were(be) you, I would give the AIDS patient a hug.
3．The accident might have been caused(cause) by a dog running across the road, but we don't know for sure.
4．He looked so hungry as though he hadn't eaten(eat) a decent meal for a month.
5．I was caught in a traffic jam for over an hour. Otherwise, I wouldn't have kept(keep) you waiting for such a long time.
6．—Polly is very late.
—She may have missed(miss) her train.
7．I didn't see her in the meetingroom this morning. She couldn't have spoken(speak) at the meeting.
8．If I had known(know) where he lived, I would have sent(send) a note to him.
9．If they had started(start) earlier than expected, they would be(be) here now.
10．Without your help, we wouldn't have achieved(achieve) so much.
Ⅱ.单句改错
1．As a kid, I loved to watch cartoons, but no matter how many times I asked to watch them, my parents would not to let me.去掉not后的to
解析 would是情态动词，表意愿，后需跟动词原形，故to多余。
2．Some classmates suggest we can go to places of interest nearby. 删除can或can→should
解析 动词suggest作“建议”讲时，后面的宾语从句中要使用虚拟语气，即“(should)＋动词原形”，所以本句可以删除can或将can改为should。
3．He mustn't be a basketball player, because he is much too short.mustn't→can't
解析 句意：他不可能是一个篮球运动员，因为他个子太矮了。表示“不可能”，应该用can't表示否定的推测，而mustn't表示“禁止”，故将mustn't改为can't。
4．Robert's new book about space exploration is fantastic.You simply could read it.could→must
解析 句意：罗伯特写的关于太空探索的新书太好了，你一定要读一读。根据句意可知应用must，故将could改为must。
5．Has he learned about computer, we would have hired him to work here.Has→Had
解析 句意：如果他懂一些电脑知识的话，我们就聘用他来这里工作了。当虚拟条件句的谓语动词含有were, should, had时，if可省略，而将were, should, had置于句首。故将Has改为Had。
6．If it rained last night, the ground would be wet now.在rained前加had
解析 此处表示与过去事实相反的假设，应用过去完成时，故在rained前加had。
7．All of us love the weekends, because we can't get up early on Saturdays and Sundays.can't→needn't
解析 根据语境可知，此处表示“不必”，而不是“不能”，故将can't改为needn't。
8．He might have gone to bed, for the light was out.might→must
解析 句意：他一定已经上床睡觉了，因为灯已经灭了。must have done表示对过去已经发生的事情的肯定推测；might have done表示对过去已经发生的事情把握不大的推测。此处表示对过去发生事情的肯定推测，故将might改为must。
9．He commanded that roads built to link castles across the land.在built前加(should) be
解析 command后面的宾语从句应用虚拟语气，且roads和build之间是被动关系，应用被动语态，故在built前加(should) be。
10．We must go to the concert tonight, but we are not sure yet.must→may
解析 句意：我们今天晚上有可能去听音乐会，但是还不确定。must表示肯定的猜测，而may意为“可能会”，表示把握不大的推测，故将must改为may。
Ⅲ.单句写作(注意正确使用情态动词和虚拟语气)
1．我的家乡春天的天气相当暖和，但有时也会非常冷。(fairly warm, extremely cold)
The weather in my hometown is fairly warm in spring, but it can be extremely cold sometimes.
2．你在山路上开车时一定要小心，因为有时可能很危险。(drive down, the mountainous road)
You must be careful when you drive down the mountainous road, because it can be dangerous sometimes.
3．在这个村子里有很好的社交生活，并且我希望我再有机会去更多地参与。(social life, have a second chance, become involved)
There is a good social life in the village, and I wish I had a second chance to become more involved.
4．现在，他不可能正在和他的同学一起旅游。相反，他一定是在家里学习。(tour with)
At the moment, he can't be touring with his friends. On the contrary, he must be studying at home.
5．是因为我学习不够努力，还是因为我学习方法不当？(work hard, in the right way)
Can it be because I haven't worked hard enough or because I haven't studied in the right way？
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