一、虚拟语气在条件句中的使用 三种 情况 if从句 主句 例句 与现在 事实相 反 主语＋动词的过去式(be的过去式用were) 主语＋would/could/might/should＋do If I were a bird，I could fly.如果我是一只鸟，我就能飞了。 三种 情况 if从句 主句 例句 与过去 事实相 反 主语＋had＋过去分词 主语＋would/ could/might/should＋have
done If we had started earlier，we should not have missed the train.如果我们早点出发，就不会错过这列火车了。 三种 情况 if从句 主句 例句 与将来 事实相 反 主语＋动词的过去式 主语＋were to do 主语＋should＋do 主语＋would/could/might/should＋do If he should not arrive on time，we would call off the meeting.万一他不能按时到，我们就取消会议。 [注意] (1)用介词with，without，but for等替代条件句。 But for your advice，I could not have done it so successfully.要是没有你的建议，我就不会那么成功。 The changes could not have taken place without the open door policy.要是没有开放政策，就没有这些变化。 (2)省略if的虚拟条件句。 if引导的虚拟条件句的谓语动词中含有had，should，were时，可将if省略。而将had，should，were置于句首，采用倒装语序，而句意不变。 Had he worked harder，he would have got through the exams.如果他学习刻苦些，他就会通过考试了。 Were she younger，she would do it. 如果她再年轻点，她会做这件事的。 Should it rain next week， the farmers would have a good harvest.倘若下周下雨，农民就会有好收成。 二、混合(时间)错综型虚拟条件句 通常情况下，在非真实条件句中主句和从句的谓语动词所指的时间是一致的，但有时也可能指不同的时间，这时要根据上下文的意思采用不同的谓语动词形式。即：从句和主句根据各自谓语动作发生的时间不同，采用相应的谓语动词形式。 1.从句表示过去，主句表示现在
If they had started the early morning yesterday，they would
be here now.
如果他们昨天一大早出发的话，他们现在该到这里了。 2.从句表示将来，主句表示过去
If I were not to make a preparation for my experiment this
afternoon，I would have gone to see the film with you last
night.如果不是准备今天下午的实验，我昨晚就和你一块
去看电影了。 3.从句表示过去，主句表示将来
If we hadn't made adequate preparations，we shouldn't
dare to do the experiment next week.
如果我们没有做好充分准备，下周我们就不敢做此实验。 4.从句表示将来，主句表示现在
If we shouldn't have an exam this afternoon，I would go
shopping now.如果今天下午我们不考试，我现在就去购
物了。 5.从句表示现在，主句表示过去
If I were you，I would have gone to her birthday party.
如果我是你，我就去参加她的生日聚会了。 6.从句表示过去，主句表示过去和现在
If you hadn‘t lent me some money，I couldn’t have bought
the new house and most likely I would be still living in the
dangerous house now.如果你不借给我钱的话，我就不能
买新房子了，而且很可能我现在仍然住在危房里。
三、虚拟语气在其他从句中的使用 1.wish的宾语从句的虚拟语气有三种情况： (1)表示现在不能实现的愿望，从句谓语动词用过去时； (2)表示过去不能实现的愿望，从句谓语动词用过去完成时； (3)表示将来不能实现的愿望，从句谓语动词用
“would/could/might＋动词原形”。
How I wish I were you！我多么希望我就是你！
I wish that I had never met her.我要是没见过她就好了。 2.hope/expect/think等动词的过去完成时后的宾语从句中，从
句谓语动词用“would＋动词原形”，表示过去未实现的愿
望或未做成的事。
I had hoped that I would stay here for about a month，but I
changed my mind.我本希望在这里要呆上大约一个月，但后
来改变了想法。 3.would rather/would prefer的宾语从句中，表示现在或将来
的情况用一般过去时；表示过去的情况，用过去完成时。
He would rather he was the person who found the spot.
他希望他就是发现现场的那个人。
She would prefer that we had the discussion right after the
lecture.她愿意我们一听完课就讨论。 4.suggest，order，demand，propose，command，request，
desire，insist等动词后的宾语从句谓语用“(should＋)动词
原形”形式。
由上述动词派生或转化来的名词的同位语从句或表语从句
中，也要用“(should＋)动词原形”的形式。这类词有：
suggestion，proposal，plan，demand，order，desire，
request，requirement，advice，decision，insistence等。
I propose that we (should) set a deadline for handing in the
plan.我提议我们应该确定一个交计划的最终期限。 They demanded that the company (should) make compensation for the loss.他们要求该公司赔偿损失。 Reluctantly she accepted their proposal that she (should) be operated.她勉强地接受他们要她去做手术的建议。 The people expressed their desire that the war (should) come to an end soon.人民表达了早日结束战争的愿望。 [注意] 当insist作“坚持要求”解，suggest作“建议”解时， 宾语从句才用虚拟语气。当insist作“坚持认为”解，sugg- est作“暗示，表明”解时，宾语从句通常不用虚拟语气。 She insisted that he was wrong.她坚持(说)他错了。 His remarks suggested that he misunderstood my position on the question. 他的话表明他误解了我在这一问题上的立场。
5.as if/though引导的状语从句或表语从句的虚拟语气与wish
宾语从句的虚拟形式相同。
She looks as if she were ten years younger than me.
她看起来好像比我年轻10岁。
She looks after the wounded monkey as if it were her baby.
她照料这只受伤的猴子，就像它是自己的孩子一样。 6.在由in case/so that/lest/for fear＋that引导的状语从句中，
谓语动词要用虚拟形式，即should/might/would＋动词原
形。
She put a blanket over the baby for fear that he should catch
cold.她在那个婴儿身上盖上了毯子以免他着凉。
He ran away lest he should be caught.
他逃走了以免被抓住。 7.It's (high/about) time＋that从句
从句的谓语动词要用过去式或should＋动词原形，表示虚
拟语气。
You‘re lazy－it’s high time that you started working hard.你
太懒了——你该开始努力工作了。 8.It is＋adj./done＋that从句
在该结构中，如果形容词或过去分词是下面一些词语，从句
谓语常用“(should＋)动词原形”，如advisable，decided，
appropriate，determined，commanded，arranged，insistent，
natural，insisted，necessary，suggested，urgent，ordered，
strange，preferable，proposed，requested，required等。
It is necessary that older people (should) understand what the
young think.
年长的人有必要了解年轻人在想些什么。
It is suggested that he often go out for a walk.
有人建议他应该经常出去走走。 9.if only引导的感叹句中，谓语动词常用虚拟语气，用一般
过去时表示现在没有实现的愿望，用过去完成时表示过去
没有实现的愿望。
If only the driver hadn‘t driven so fast！
要是那位司机没开那么快就好了！