语法专题七 虚拟语气
英语中有三种不同的语气：陈述语气，祈使语气和虚拟语气。虚拟语气表示说话人的愿望、假设、猜测或建议，而不表示客观存在的事实。
考点一 虚拟语气用于条件句中
1．表示与现在事实相反：条件状语从句中谓语动词用一般过去时（be的过去式用were）；主句中谓语动词用would（should，could，might）＋动词原形。
If I were you，I would study hard.
2．表示与过去事实相反：条件状语从句中谓语动词用had＋过去分词；主句中谓语动词用would（should，could，might）＋have＋过去分词。
If he had taken my advice，he would have passed the test.
3．表示与将来的事实相反：条件状语从句中谓语动词用一般过去时或should＋动词原形或were to＋动词原形；主句中谓语动词用would（should，could，might）＋动词原形。
If it were to rain tomorrow，they would not go to the cinema.
注意：1）if条件句中只要用了过去的时态就说明该句要使用虚拟语气。
2）if条件句中只出现一个表示与将来事实相反的情态动词should。
3）含有if条件句的虚拟语气中，主句都要用情态动词，且都可理解为过去式。
考点二 wish宾语从句中的虚拟语气用法
在wish后的宾语从句中，表示与现在或过去的事实相反，或对将来的主观愿望，从句中通常用虚拟语气。从句中谓语动词的构成形式为：
1．表示对现在情况的虚拟，从句中谓语动词用过去式（be动词一般用were）。
I wish it were spring now.
2．表示对过去情况的虚拟，从句中谓语动词常用had＋过去分词。
I wish he had come yesterday.
3．表示对将来的主观愿望，从句中动词常用would/could/might＋动词原形。
I wish it would be fine tomorrow.
考点三 谓语动词必须用“（should）＋动词原形”的情况
1．表示“建议，要求，命令”的动词：一坚持（insist），二命令（order，command），三建议（suggest，propose，advise），四要求（demand，require，request，ask）后面的宾语从句或是由it作形式主语的主语从句中的谓语动词要用“（should）＋动词原形”。这些词相应的名词后的表语从句和同位语从句中的谓语动词也要用“（should）＋动词原形”。
The teacher ordered that the homework（should）be handed in on time.
It is suggested that the meeting（should）be put off.
My idea is that we（should）think it over.
注意： suggest作“表明，暗示”讲时，不用虚拟语气；insist作“坚持认为”讲时，不用虚拟语气。
The smile on his face suggested he was happy.
The boy insisted he hadn't stolen the money.
2．在It is important /strange/ natural/ necessary/a pity/a shame等＋that从句，表示情绪、观点等，主语从句中的谓语动词用“（should）＋动词原形”，should可以省略。
It is a pity that he（should）refuse to accept the offer.
考点四 虚拟语气在其他句型中的使用
1．在as if/ as though引导的状语从句中，若从句与事实相反，则要用虚拟语气。其形式如下：
主语＋as if/ though＋主语＋一般过去时（从句的动作与主句动作同时发生）
主语＋as if/ though＋主语＋would/could＋动词原形（从句的动作相对主句来说在将来发生）
主语＋as if/ though＋主语＋过去完成时（从句的动作先发生于主句动作之前）
He talks as if he knew all about it. He walked slowly as though he had hurt his leg.
2．在It is（high）time that...句型中也用虚拟语气，从句常用过去式，有时也用should＋动词原形，should不可以省略。表示“是时候做……了”，含“建议”的意味。
It is time that we studied hard.
3．would rather后接动词原形，但接从句时要用虚拟语气（宁愿，但愿）。
would rather＋主语＋一般过去时（表示与现在或将来情况相反）
would rather＋主语＋过去完成时（表示与过去事实相反）
I'd rather he didn't go now.
I'd rather you hadn't told Mike the bad news.
4．if only “要是……就好了”。表示与现在或未来事实相反的愿望时，句子谓语动词用一般过去时；表示与过去事实相反的愿望时，句子谓语动词用过去完成时。
If only I had passed the driving test last week! 5．动词hope，intend，mean，plan，want，think等词的过去完成时形式，通常表示“本想，本打算，本认为”。
He had hoped to come to the party，but it began to rain.
考点五 含蓄虚拟条件句
有时候假设的情况不以if引导的条件句形式表现出来，而是通过一个介词短语、连词或其他形式表示。常用的词或短语有：without，with，but for（要是没有），otherwise，or，but等。
Without your help（＝If we had not had your help），we could not have finished the task.
He felt very tired yesterday，or/otherwise he would have come to the party.
考点六 错综时间条件句中的虚拟语气
当条件状语从句表示的行为和主句表示的行为所发生的时间不一致时，称为“错综时间条件句”，动词的形式要根据各自主从句所表示的时间作出相应的调整。
If you had followed my advice，you would recover.（从句说的是过去，主句说的是现在）
If I were you，I would have gone abroad.（从句是现在，主句说的是过去）
考点七 省略if的虚拟语气如果if从句中含有were/ should/ had时，则可以省略if，把这三个词置于句首，采用倒装语序。
If I were you，I would go to the party.→Were I you，I would go to the party.
If it should happen，what would you do？→Should it happen，what would you do?
If you had come earlier，you would catch the bus.→Had you come earlier，you would catch the bus.
1．（2012·北京高考）Don't handle the vase as if it ______ made of steel.
A．is B．were
C．has been
D．had been
2．（2012·浙江高考）Had they known what was coming next，they ______ second thoughts.
A．may have
B．could have
C．must have had
D．might have had
3．（2012·陕西高考）If my car ______ more reliable，I would have driven to Lhasa instead of flying last summer.
A．was
B．had been
C．should be
D．would be
4．（2012·辽宁高考）Jack is a great talker.It's high time that he ______ something instead of just talking.
A．will do
B．has done
C．do
D．did
5．（2012·山东高考）If we ______ adequate preparations, the conference wouldn't have been so successful.
A．haven't made
B．wouldn't make
C．didn't make
D．hadn't made
6．（2012·安徽高考）Grace doesn't want to move to New York because she thinks if she ______ there，she wouldn't be able to see her parents very often.
A．lives
B．would live
C．has lived
D．were to live
7．（2012·福建高考）We lost our way in that small village，otherwise we ______ more places of interest yesterday.
A．visited
B．had visited
C．would visit
D．would have visited
8．（2012·湖南高考）Sorry，I am too busy now.If I ______ time，I would certainly go for an outing with you.
A．have had
B．had had
C．have
D．had
9．（2012·天津高考）We would have called a taxi yesterday if Harold ______ us a ride home.
A．didn't offer
B．wouldn't offer
C．hasn't offered
D．hadn't offered
10．（2011·课标全国高考）They ______ have arrived at lunchtime but their flight was delayed.
A．will
B．can
C．must
D．should
11．（2011·北京高考）—Where are the children？The dinner's going to be completely ruined.
—I wish they ______ always late.
A．weren't
B．hadn't been
C．wouldn't be
D．wouldn't have been
12．（2011·北京高考）Maybe if I ______ science，and not literature then，I would be able to give you more help.
A．studied
B．would study
C．had studied
D．was studying
13．（2011·天津高考）I ______ sooner but I didn't know that they were waiting for me.
A．had come
B．was coming
C．would come
D．would have come
14．（2011·福建高考）—Pity you missed the lecture on nuclear pollution.
—I ______ it，but I was busy preparing for a job interview.
A．attended
B．had attended
C．would attend
D．would have attended
15．（2011·陕西高考）I______through that bitter period without your generous help.
A．couldn't have gone
B．didn't go
C．wouldn't go
D．hadn't gone
16．（2011·江西高考）We ______ John's name on the race list yesterday but for his recent injury.
A．will put
B．will have put
C．would put
D．would have put17．What's your opinion of Mr Li's request that we ______ spend half an hour reading English aloud every morning?
A．must
B．would
C．should
D．could
18．I ran all the way to school yesterday，otherwise I ______ late for the annual talent show.
A．was
B．had been
C．would be
D．would have been
19．—What's your feeling now?
—I am terribly sorry.If only I ______here yesterday!
A．came
B．would have come
C．have come
D．had come
20．（2016·河北普通高中教学质监）I would have grabbed the ball if I ______ closer to it.
A．was
B．were
C．would be
D．had been
21．（2016·山西第二次四校联考）It's everybody's desire that every effort ______ to reduce the pollution in our city.
A．was made
B．be madeC．will be made
D．would be made
22．（2016·北京东城区示范校综合练习一）If he had decided where to go，he ______ on his way at present.
A．would be
B．would have been
C．is
D．were
23．（2016·河南中原名校联考）Without your selfless help，I ______ such great progress.
A． can't make
B．couldn't have made
C．couldn't make
D．wouldn't make
24．（2016·浙江名校联盟第一次联考）______ a little earlier，you could have got a copy of his latest book.
A．If you would arrive
B．If you arrived
C．Should you arrive
D．Had you arrived
25．（2016·河南中原名校联考）—How I wish I ______ the key with me!
—Then you would not have to wait for your wife's rescue.
A．had had
B．have had
C．had
D．have
1．B as if 条件句用虚拟语气表示与现在的事实相反。句意：不要对待那个花瓶像它是由钢制成似的。
2．D 句意：如果他们知道接下来会发生什么，他们可能就会再三考虑了。表示与过去事实相反的虚拟，主句用“might/could/should/would＋have done”。
3．B 根据would have driven 可知是与过去的事实相反，故if 条件句用过去完成时。句意：如果我的车子再可靠一点的话，我就会开车而不是乘飞机去拉萨了。
4．D 句意：杰克是个空谈家。到了他做点事而不是夸夸其谈的时候了。it is high time从句中要用虚拟语气，其谓语动词多用一般过去时，或是should＋动词原形，should 不能省略。故只有D项正确。
5．D 在if引导的条件虚拟句中，与过去情况相反的条件句用had done的形式，主句谓语为“情态动词＋have done”形式。句意：如果我们没有做好充分的准备，会议也就不会那么顺利。故选D项。
6．D 句意：格雷斯不想搬到纽约去，因为她认为如果她住在那儿的话，就不能经常见到她的父母了。由句意可知，这是对将来事情的虚拟。故主句中要用“would＋动词原形”，条件句中可以用were to do, 一般过去时态或者should ＋ do。所以只有D项符合题意。
7．D 由句子中的“我们在那个小村庄里迷了路”与otherwise可想到本题考查对过去事情的虚拟语气；otherwise等于if we hadn't lost our way in that small village，因此其主句的谓语应用“would have done”的形式，故答案为D项。
8．D 句意：很抱歉，我现在很忙。要是我有时间，一定会与你去远足的。根据句意可知，此处表示与现在事实相反的虚拟语气，条件句中的谓语动词要用过去式。故D项正确。
9．D 句意：昨天，如果不是哈罗德让我们搭他的车回家，我们就叫辆出租车了。表示与过去事实相反的虚拟语气，条件句的谓语动词用过去完成时。
10．D should have done意为“本该做某事（但实际上未做）”，符合句意。句意：他们本该在午饭的时候到达，但是他们的航班延误了。A项为将来完成时；B项的can表推测，不能用于肯定句中；C项构成must have done结构，表示“一定做过某事”。
11．A 本题是考查wish后接虚拟语气的用法，而且是对现在情况的虚拟，应用一般过去时表示。句意：——孩子们到哪儿去了？饭菜快凉了。——真希望他们不要总这么晚。
12．C 由“if I ...then”可知，从句是对过去事情的虚拟，应用过去完成时。句意：或许当时如果我学自然科学而不学文学的话，我就会给你更多的帮助。故选C项。
13．D 由空后的but I didn't know that they were waiting for me可知“我”并没有早点来，因此第一句是一个虚拟语气的句子。因为讲述的过去的事情，所以句子应借助于“would＋have＋过去分词”的形式。本句可以改为以下形式：I would have come sooner if I had known that they were waiting for me.句意：我本来能够早点来，但是我不知道他们在等着我。故选D项。
14．D 由but后的I was busy preparing for a job interview可知说话者并没有去听演讲，因此此处应是一个表示过去情况的虚拟语气。对过去的事情进行虚拟时，主句应用“would＋have＋过去分词”。本句可以改为I would have attended it if I hadn't been busy preparing for a job interview.句意：——你错过了关于核污染的演讲真是遗憾。——我本想去参加的，但是我正忙着准备工作面试。故选D项。
15．A 句意：如果没有你们慷慨相助，我不可能度过那段艰辛的岁月。表达与过去事实相反的虚拟时，主句用“would/could/should/might＋have done”，故选A项。
16．D 句意：要不是因为约翰最近受伤的缘故，我们昨天就把他的名字写在参赛名单上了。根据句意及“but for（倘若没有，要不是）”可知，这里考查针对过去的虚拟，所以主句谓语部分要由would/could/might/should＋have done的形式构成，答案为D项。
17．C request 后面的名词性从句要用虚拟语气，即“（should）＋动词原形”。
18．D 句意：昨天我一路跑到学校，不然年度才艺表演我就会迟到。本句的后半句是虚拟语气，是对过去情况的假设，所以用would have done结构。
19．D if only 意为“要是……就好了”，由时间状语yesterday来看，这是对过去所发生事情的虚拟，所以用过去完成时。
20．D 从前面的would have grabbed可知，这里是与过去事实相反的虚拟语气，故if从句用过去完成时态。
21．B desire作名词时，其后的同位语从句中要用“should＋do”的虚拟语气形式，should可以省略。
22．A 这是错综时间的虚拟语气。从句与过去事实相反，故用过去完成时；从at present可知，主句与现在事实相反，故用would be的形式。
23．B 句意：如果没有你无私的帮助，我就不可能取得这么大的进步。这是与过去事实相反的虚拟语气，故主句用“情态动词＋have＋done”的形式。
24．D 从后面的could have got可知，这是与过去事实相反的虚拟语气，故从句用过去完成时态，if省略时，用倒装语序，故选D项。
25．C wish后面的从句中要用虚拟语气，这是与现在事实相反的虚拟语气，故用一般过去时态。这里的意思是“我多么希望我现在带着钥匙啊”。