虚拟语气一、语气的种类。
1．陈述语气。
表示动作或状态是客观存在的、确定的或符合事实的，用于陈述句、疑问句和某些感叹句中。
Eg：Iraq is an Asian country. （肯定句）伊拉克是亚洲国家。
The US and British armies did not start the Second Gulf War until March 20, 2003. （否定句）美英联军于2003年3月20日发动了第二次海湾战争。
Who was it that they want to help? （疑问句）他们想要帮忙的人到底是谁呀？How interesting my stay in China has been! （感叹句）我在中国的日子过的真是有趣！2．祈使语气。
表示说话人对对方的请求、警告或命令。
Eg: Please come over here.请到这边来。
Would you be so kind as to lend me a hand?请帮个忙好吗？Watch your steps!当心！（走路）Never be late again!再也不要迟到了。
3．虚拟语气。
虚拟语气表示说话人的主观愿望、猜测、建议或与事实不符合的假设等，而不表示客观存在的事实。
虚拟语气是由谓语动词的特殊形势表示出来的。
Eg: If I were a bird, I would be able to fly in the air.如果我是一只小鸟，我就能在空中飞行。
I wish I could pass the examination.我希望我能通过考试。
May you succeed!祝您成功！If only we had been college students last year!去年我们要是大学生就好了！二、虚拟语气的用法。
1.虚拟语气用在简单句中。
表示祝愿、命令。
Eg: May you be happy.祝你幸福。
May you have a pleasant journey.祝你旅途愉快。
May the friendship between us last long.祝愿我们的友谊天长地久。
2.虚拟语气用在复合句中。
（虚拟语气用于宾语从句）常跟在动词wish, suggest, order, insist, propose等词后面的宾语从句中，表示的是一种虚拟语气，宾语从句中的动作表示的只是一种愿望、要求。
（1）在wish后的宾语从句中，be动词常用“were-型”表虚拟语气，行为动词用一般过去时替代一般现在时。
（a）表示现在的愿望和将来的愿望，宾语从句中的谓语动词要用过去式（be通常用were）或would, could, might+动词原形。
Eg: I wish she would be on my side.我希望她能站在我这边。
I wish I could help him.我希望我能够帮助他。
（b）表示过去的愿望，宾语从句谓语动词要用过去完成时或would, could, might+过去分词。
Eg: I wish I had been with her last weekend.我希望上周末和她在一起。
How I wished it hadn’t been snowing while I was there！多么希望我在那边时不是一直都在下雪啊！注：were-型虚拟式只有一种形式，即不管主语是什么人称，动词一律用were，如果动词为进行体或被动语态，其助动词也一律用were。
例题：--Would you like to go to the cinema tonight?--I wish I ______, but I have to study for a test.A. hadB. shouldC. couldD. did（2）在动词suggest(建议)，demand(要求)，order(命令)，propose(建议)，insist(坚持)，command(命令)，request(要求)，desire(希望)后面的从句中，动词用“should-型”虚拟式，即：should+动词原形，表示建议、要求、命令等。
Should可以省略。
Eg：The teacher suggested that we (should) clean the blackboard after class.老师建议我们课后把黑板擦了。
He ordered that the students wash the clothes every week by themselves.他要求学生每周都要自己洗衣服。
He insists that all of us should be there on time by any means.他坚持要我们大家想尽办法按时去那儿。
I suggest that we (should) start the meeting at once.我建议马上开会。
The undergraduate insisted that he (should) go to work in the south.这位即将毕业的学生坚持要到南方去工作。
注：1—当suggest表示“暗示”时，后接的宾语从句不用虚拟语气。
Eg：His silence suggested that he agreed with my decision.他的沉默暗示着他赞成我的决定。
He suggested that I (should) stick to my decision.他建议我坚持自己的决定。
2—当insist表示“坚持（说/认为）”时，后接的宾语从句不用虚拟语气。
Eg：He insists that doing morning exercise does good to people’s health.他坚持认为做早操对健康有益。
He insists that he (should) do morning exercise every day.他坚持每天都要做早操。
3—当ask表示“问”时，后接的宾语从句应当用真实语气，而在表示“要求”时，则用法类似require/request，用虚拟语气。
Eg：He asked us if we had wanted to visit the Summer Palace.他问我们是否本来想去参观颐和园。
He asks that he (should) be given the chance.他要求得到这个机会。
例题：1. --What did the doctor say about your mother’s illness?--He suggested that she ______an operation at once.A. must haveB. hadC. haveD. had had2. The teacher demanded that the exam ______before election.A.Would be finishedB. must be finishedC.be finishedD. must be finishing（虚拟语气用于表语从句）（1）当主语为before, suggestion, order, proposal, demand等词时，后接that引导的表语从句，表语从句中的谓语动词常用“should+动词原形”结构，表示建议、劝告、命令的内容。
Eg: My advice is that you should practice speaking English as often as possible.我的建议是你尽可能的经常练习说英语。
The order from the commander was that the troops should set off for the front immediately.司令官的命令是部队立即出发去前线。
（2）当宾语为advice, suggestion, order, proposal, demand等词时，后接that引导的同位语从句，从句谓语动词用“should+动词原形”，说明所提的建议、劝告、命令等的内容。
Eg: He gave us some advice that we should pay attention to our pronunciation.他给我们的忠告是要重视发音。
Mr. Li put forward a suggestion that the meeting should be put off until next Monday.李先生建议会议推迟到下周一。
（3）a s if, as though引导的表语从句，如果表示与事实和可能出现的事实相反的假设，be动词用“were-型”虚拟式，行动动词用过去完成时。
Eg：He looks as if he were his father.他看起来像他爸爸。
He seemed as though he had known everything.他好像什么都知道似的。
（事实上他并不知道。
）注：当as if, as though引导的表语从句不表示与事实或可能出现的事实相反的假设时，则不用虚拟语气。
Eg：Tom looks as if he’s been told about the car accident already.看起来好像汤姆已经获悉这起汽车事故。
例题：When a pencil is partly in a glass of water, it looks as if it_______.A. breaksB. has brokenC. were brokenD. had broken（虚拟语气用于主语从句）在句型“It is important(necessary, strange, natural)that…”, that 从句中的谓语动词用“should+动词原形”。
Eg：It’s necessary that we should have a walk now.现在我们有必要出去散散步。
It’s natural that she (should) be taken good care of.她得到很好的照顾是很自然的。
It’s important that we should take good care of the patient.重要的是我们要照顾好病人。
（虚拟语气用于if引导的条件状语从句）虚拟语气最多地用在表示条件的状语从句和表示结果的主句中。