1状语从句中的虚拟语气虚拟语气在if引导的条件句中的用法三点：从句（条件）主句（目的）表示于现在事实相反的虚拟条件句If+主语+动词的过去式（be用were）If I had time,I would attendthe meeting.
主语+would(should couldmight)+动词原型表示与过去事实相反的拟条件句If+主语+had+动词的过去分词If he had hurried,he couldhave caught the train.
主语+would（should couldmight）+have+动词的过去分词表示与将来事实相反的虚拟条件句1、If+主语+动词过去式2、If+主语+were to+动词原形3、If+主语+should+动词原形If I were to go abroad,I wouldgo to America.
主语+would（could shouldmight）+动词原型错综时间条件句——主从句时间不一致的情况下的虚拟语气有时条件从句中的动作与主句中的动作，发生的时间不一致，这是动作的形式应根据它所表示的时间加以调整。
If you had followed my advice,you would be better now.
If you had studied hard before,you would be a college student now.
含蓄条件句有时虚拟条件句并没用if从句表示出来，而是用介词短语（otherwise，or，without，but for）上下文或其他方式来表示。
1.条件暗含在短语中；2.条件暗含在上下文中；3.虚拟式变为习惯说法，很难找出其暗含的条件。
条件从句中省略if采用倒装语序的情况在if引导的表示虚拟的条件状语从句中，有时可以把虚拟条件中的连词if省去，而将had，should，were等助动词提到主语之前。
例：原句：1:If she were younger,she,would do it.
去if：Were she younger,she,would do it.
2:If you had come earlier,you would have met him.
去if:Had you come earlier,you would have met him3:If it should rain tomorrow,we would not go climbing.
去if:Should it rain tomorrow,we would not go climbing.
2虚拟语气在as if/asthough引导的方式状语从句中1.表示与现在事实相反或对现在情况有怀疑，谓语动词用过去式。
He treats the boy as if he were his own son.
2.表示与过去事实相反，谓语动词用过去完成时。
He spoke as if he had known about it.
3．表示与将来事实相反，(表示将来的可能性不大),用would(might,could)+动词原形He acts as if he could win in the game.
注意：1.在as if/as though句中，如果有可能成为事实，用陈述语气。
例：He looks as if he going to be ill.
2.as though或as if引导的状语从句，从句主语和主句主语相同时，从句中可省略主语和部分谓语。
虚拟语气用在lest，forfear that，so that及inorder that引导的目的状语从句中表示“以防，以免”等意思谓语动词多用should/could/might+动词原型构成For fear that it may rain tomorrow,we should bring an umbrella.
由“providing（that）/provided（that）/oncondition that/suppose（that）/supposing（that）”引导的条件从句根据情况，1.可以用虚拟语气。
例：suppose/supposing that it rained,we shouldn’t goout.
2.也可以用陈述语气。
例：They are willing to surrender provided they aregiven free pardon..
3“In case”引导的从句中即可用陈述句，也可以用虚拟语气（should）+动词原型例：1.The game will be put off in case it(should)snow.
2.The game will be put off in case it snows.
名词性从句中的虚拟语气一：宾语从句中的虚拟语气1.在动词wish/hope后的宾语从句中的虚拟语气,表示一种不可能实现的愿望。
对现在情况的虚拟：从句谓语动词用过去式或过去进行式。
I wish(that)I were a bird.
对过去情况的虚拟：从句谓语动词用过去完成时，或would，could，might+现在完成时。
I wish(that)I had seen the film last night.
对将来情况的虚拟：从句谓语“would/should/could/might+动词原形”。
I wish(that)I would\could go.
在表示建议，命令，要求，忠告，等动词的后面的宾语从句中的虚拟语气均以“should+动词原型”表示这种语气，“should”常被省略。
We suggested that the meeting(should)be put off.
They insisted that the boy(should)go with them.
常用的此类动词有：表示“提议，劝告，建议”的：propose,suggest,recommend,advise.
表示“要求”的：ask,desire,request,demand,require,beg表示“同意，坚持”的：insist表示“决定，命令”的：decide,order注意：suggest,insist不表示建议或坚持要某人做某事时，即它们用于其本意暗示，表明，坚持认为时，宾语从句用陈述语气。
The smile on his face suggested(暗示）that he was satisfied with ourwork.
The man insisted【坚持认为】that he had never stolen the money.
在expect，believe，think，suspect等动词的否定或疑问形式后的宾语从句中的虚拟语气经常用“should+动词原型（或完成形式），表示惊奇，怀疑，不满等情绪。
I cannot believe that you should think so.
Would rather，hadrather，后的宾语从句中的虚拟语气谓语动词用过去式表示与现在或将来相反I would rather you told me the truth.
4用过去完成式表示与过去事实相反。表示“宁愿做什么”或“对过去做的事的懊悔”。
I would rather you had gone there last Sunday.
注意：1.若某人愿自己做某事，would rather后用动词原型2.would rather⋯..than⋯⋯中用动词原型I would rather do it by myself.
I would rather watch TV at home than go to thecinema.
主语从句中的虚拟语气“It is(was)+形容词（或过去分词）+that⋯.”结构中的虚拟语气表达形式为should+动词原形或省略shouldIt’s quite necessary that we should have a walk now.
常用的形容词：natural，appropriate，advisable，necessary，important，urgent，probable，possible，desirable，strange。
注意：在上述所列形容词后面用that引出的宾语从句中，谓语动词也要用虚拟语气。
例：I don’t think it advisable that tom be assigned to the job since hehas no experience.(汤姆缺乏经验，指派他做这项工作我认为是不恰当的).
在“It is(was)+名词+that⋯..”结构句中的虚拟语气表示建议，命令，请求，道歉，怀疑，惊奇等。
It’s a pity that you(should)miss a good chance.
这类名词有：advice，decision，desire，demand，idea，order，pity，proposal，recommendation，suggestion，surprise，wish，wonder等。
表语从句或同位语从句中的虚拟语气某些表示建议，请求，命令等主观意向的名词做主语时，其后的表语从句或同位语从表达形式为should+动词原型或直接用动词原型。
My idea is that we(should)think it over before accepting it.
We all agree to that suggestion that the meeting(should)be put off.
在It is demanded/suggested/ordered/required⋯.
5句需用虚拟语气that-clause句型中从句用(should)+动词原型It is demanded that we should work out a plan.
这类名词常见的有：demand，desire，requirement，advice，recommendation，suggestion，order，necessity，proposal，plan，idea。
在It is(about/high)time+that定语从句中的虚拟语气表示“该做⋯⋯..的时候了”其动词形式用一般过去时或should+动词原型It is high time that you went/should go to school.
注意：在this is the first time/second time that⋯.句型中，从句中谓语动词用陈述语气完成时态。
This is the second time that we have achieved such a great success.
If only引起的感叹句中的虚拟语气If only引出感叹句，意思是“要是⋯..多好”，表示说话人的一种愿望。
表示现在的情况,应用过去式;表示过去的情况,应用过去完成时态表示将来的情况，用would+动词原形例：If only he didn’t drive so fast!(现在)Look at the terrible situation I am in!if only I had followed youradvice(过去)If only the rain would stop.(将来)even if(even though)引导的让步状语从句中的虚拟语气6表示一种让步语气，即使...也做不成某事。
表示现在的情况,应用过去式表示过去的情况,应用过去完成时态Even if he were here,he could not solve the problem.
Even if I had been busy then,I would have helped you.
Choose the best answer:It is strange that the little boy_____speak two foreign languages.
A.could b.can C.should D.would2.He gave orders that the experiment____before 5:30pm.
A.be finished B.will finish C.must be finished3.He_____you more help,even though he was very busy.
A,might have given B.might give C.may have given4.Without the leadership of the Party,there____no New China.
A.would be B.has been C.should be D.was5.He is talking so much about America as if he_____there.
had been B.has beenC.was D.has gone6.The young man insisted that he_____nothing。
