湫椭校瑃hat 引导的从句用虚拟语气，即谓语动词用should ＋ 动词原形；should可以省略。这个句型表示说话人的意见、要求等。For example：
It is essential that there should be enough food and clothing for the winter。
It is desirable that your wedding be postponed until next July。
It is imperative that the board chairman be present at the board meeting。另外，在一些习惯用语中也有虚拟语气的形式。但最好把这些习惯用语作为一种句型来记住。如：
May you be happy！
May you succeed！
Long live the People’s Republic of China！
Everybody leave the room！
You had better not resign。
I would rather not tell you。总之，虚拟语气是英语中的一个难点，因为虚拟语气的用法和句型较多，动词的变化比较复杂。在学习的时候要逐个过关。同时，也要善于发现虚拟语气的规律。根据动词的变化，大致可以把虚拟语气分为三种：
一种是动词用过去式，过去分词式，或过去将来式，这主要是用if…； wish； suppose的情况；
一种是动词用should＋动词原形（should可以省略），这主要用于表示建议、要求、命令等意思的动词或名词后面所接的从句，以及It is important （necessary） that…后面所接的从句；
一种是动词用过去式，如It is （high） time （that）…和I would rather 后面的从句。同学们还可以自己总结适合自己的规律，如把虚拟语气句型可以分为用于简单句、条件状语从句、宾语从句、主语从句、表语从句、定语从句、同位语从句等。
Now let’s do some exercises to consolidate what we have learned about subjunctive mood：一、单项选择：1。 The teacher demanded that the exam ___before eleven。
a。 must finish b。 would be finished c。 be finished d。 must be finished2。 She made the demand that she ____ at once。
a。 leave b。 leaves c。 left d。 to be left3。 He is talking so much about America as if he ____ there。
a。 had been b。 has been c。 was d。 been4。 Mother insisted that the child’s hands ___ before dinner。
a。 should wash b。 be washed c。 would wash d。 had washed5。 The young man insisted that he ___ nothing wrong and ____ free。
a。 did； set b。 had done； should be set c。 do； be set d。 had done； must be set6。 Mother suggested that I ___ my homework first before watching TV。
a。 did b。 do c。 shall do d。 have done7。 My suggestion was that the meeting ____ off till next week。
a。 to put b。 be put c。 should put d。 be putting8。 The suggestion has been made ___the basketball game ___ put off。
a。 for； to b。 that； be c。 which； should be d。 to； being9。 The mander ordered that the wounded ___ to hospital right away。
a。 to be sent b。 be sent c。 send d。 should send10。 The order came that the medical suppliers ____ to the village without delay。
a。 would be sent b。 should send c。 be sent d。 must be sent11。 They requested that he ____ on the radio
a。 spoke b。 speaks c。 speak d。 would speak12。 It is important that we ___ wild animals。
a。 will protect b。 should protect c。 shall protect d。 are protecting13。 It is necessary that the problem ____ at once。
a。 solves b。 should solve c。 should be solved d。 will be solved14。 It is strange that he ____ interest in much of his research。
a。 should have lost b。 would lose c。 had lost d。 will lose15。 Had you listened to the doctor； you ___ all right now。
a。 are b。 were c。 would be d。 would have been16。 ___ I be free tomorrow； I could go with you。
a。 Could b。 Should c。 Might d。 Must17。 ___ to do the work； I should do it some other way。
a。 If were I B。 I were c。 Were I d。 Was I18。 ___ today； he would get there by Friday。
a。 Would he leave b。 Was he leaving c。 Were he to leave d。 If he leave19。 ____ your letter； I would have written back two days ago。
a。 If I received b。 Should I receive c。 Had I received d。 If I could have received20。 ____； he would have passed the exam。
a。 If he were to study b。 If he studied hard
c。 Had he studied hard d。 Should he study hard21。 Should it rain； the crops ___。
a。 would be saved b。 would have been saved c。 will be saved d。 had been saved22。 You ___ earlier。 The bus left a moment ago。
a。 would e b。 should have e c。 may e d。 have e23。 He treated me as though ___ his own son。
a。 I am b。 I would be c。 I was d。 I were24。 He smiled as if he ____ my thought。
a。 read b。 was reading c。 had read d。 has read25。 I ____ you some money； but I hadn’t any on me then。
a。 would lend b。 would have lent c。 could lend d。 may have lent26。 He talks as if he ____。a。 knows all about it b。 has known all about it c。 knew all about it d。 knowing all about it27。 “Have you ever been to Beijing？” “No； but I wish I ___。”
a。 have b。 will c。 do d。 had28。 Where is Xiao Zhang？ I wish I ____ him at once。
a。 can find b。 will find c。 could find d。 could have found29。 I wish I ___ there then。
a。 was b。 were c。 had been d。 would be30。 It is time we ___ to bed。
a。 must go b。 will go c。 went d。 have gone31。 If I ____ you； I would try again。
a。 am b。 was c。 were d。 be32。 _____； all the students would hear。
a。 If the teacher had spoken louder b。 If the teacher will speak louder
c。 Had the teacher spoken louder d。 If the teacher spoke louder33。 What should we do if it ____ tomorrow？
a。 should snow b。 would snow c。 snow d。 will snow34。 If you _____ 5 minutes earlier； you _____ him。
a。 should e； had seen b。 came； would see
c。 e； will see ？d。 had e； would have seen35。 If only I ____ my watch。
a。 hadn’t lost b。 haven’t lost c。 didn’t lose d。 don’t lose36。 You _____ such a serious mistake if you had followed his advice。
a。 may not make b。 might have not madec。 shouldn’t have made d。 might not have made37。 He ____ the test； but he wasn’t careful enough。
a。 could have passed b。 were able to pass c。 must have passed d。 might be able to pass38。 We ____ the work on time without your help。
a。 hadn’t finished b。 didn’t have finished c。 couldn’t have finished d。 can’t have finished39。 If you ____ at school； you _____ a college student now。
a。 had studied hard； would have been b。 should have studied hard； should have been
c。 had studied hard； would be d。 would study hard； must have been40。 If only I ____ as young as you are！
a。 being b。 am c。 be d。 were
二、改错1。 I wish that it is true。答案：is 改为were2。 The doctor suggests that she will not smoke。答案：will 改为should； 或去掉will3。 She insists that they must give her a receipt。答案：must 改为should； 或去掉must4。 Bill wished that he is more interested in his work。答案：is改为were5。 He would be a good sportsman now if he trained regularly。答案：trained 前面加上had6。 I wish that somebody teaches me to sew。答案：teaches 改为taught7。 I wish that you saw the charming opera yesterday。答案：saw 改为had seen8。 This is not my dictionary。 If it is mine I will lend it to you。答案：第二句话改为If it were mine I would lend it to you。9。 If my watch were not slow yesterday； I would not have been late。答案：wer