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1、Conditional Sentence 条件句Key PointsType I Type IV ConditionalsMixed Conditionals Replacing ifOmitting if if vs.when;in case vs.if 34.1 IntroductionConditional sentences consist of 2 partsone that expresses the conditionIntroduced by the word“if”,commonly known as“if clause”.one that expresses the con
2、sequence.Example:If you work hard,you will succeed.If a boy looks at me,I am flattered.There are four main types of conditional patterns.Type I:whenever-type real conditionalType II:probable real conditionalType III:improbable unreal conditionalType IV:imaginary unreal conditional34.2 Type I:wheneve
3、r-type real conditionalUse:to denote universal truths or general validity to denote present habitual actions to denote past habitual actionsIf=when/whenever/every timeIf clausemain clause Simple present Simple pastSimple present Simple pastIf you pour oil on water,it floats.If I make a promise,If th
4、e weather was nice,I keep it.she often walked to work.34.3 Type II:Probable Real ConditionalUsed for talking about possibilities in the present or in the future.If clausemain clause Simple Present will-future imperative modal+infinitive If I study,I will pass the exams.If you see John tonight,If Ben
5、 gets up early tell him to e-mail me.he can catch the bus.Exercise 1如果核武器用于世界大战，世界就会毁灭。If nuclear weapons are employed in a world war,the world will be destroyed.Exercise 2Make up a sentence using the following phrases.Examplelazy,fail in exam If youre lazy,youll be failed in the exam.1.not rain tom
6、orrow,go for a picnic Answer 2.go to school on foot,late Answer 3.do not have breakfast,hungry Answer34.4 Type III:Improbable Unreal ConditionalUsed for talking about unreal situations in the present or in the future.If clausemain clause Simple Past would infinitive could infinitive might infinitive
7、 If I had a day off from work next week,I would go to the beach.I could go to the beach.I might go to the beach.Exercise 3年龄大的人如果离开农场，就会发现找份工作很难。The older men would find it difficult to get a job if they left the farm.如果要问我的感受的话，我就会说“烦”。If I were asked to define my condition,Id say“bored”.34.5 Type
8、IV:Imaginary Unreal ConditionalUsed for talking about unreal situations in the past If clausemain clause(If)had ed-participle would have ed-participle.could have ed-participle.might have ed-participle.If I had studied,I would have passed the exams.I could have passed the exams.I might have passed th
9、e exams.Exercise 4 如果她未结婚的话，她可能会在她的领域中有所成就。If she had not married,she would probably have become something special in her field.Exercise 5Try to distinguish the following sentences.1.If you take a taxi,you can get there in time for the play.Type I Type II Type III Type IV 2.If I had known your arriv
10、al,I should have met you.Type I Type II Type III Type IV 3.If the weather is nice,she walks to work.Type I Type II Type III Type IV4.If I dropped this bomb,it would explode.Type I Type II Type III Type IV Exercise 55.If I were you,I would not listen to him.Type I Type II Type III Type IV 6.If you ha
11、d recognized him,you would have spoken to him.Type I Type II Type III Type IV 7.If I went to a friends house for dinner,I usually took a bottle of wine or some flowers.Type I Type II Type III Type IV 8.Set your alarm clock,and you will not oversleep.Type I Type II Type III Type IV 34.6 Mixed Conditi
12、onals1 Sometimes Unreal Conditional sentences are mixed.This means that the time in the if-clause is not the same as the time in the result.PAST PRESENT If I had won the lottery,I would be rich.PAST FutureIf she had signed up for the ski trip last week,she would join us tomorrow.PRESENT PASTIf Sam s
13、poke Russian,he would have translated the letter for you.34.6 Mixed Conditionals2 Sometimes the validity of the if-clause is not the same as the validity of the result.Unreal RealI might have seen him,but he didnt come to the party.Real UnrealHe isnt here now,or he would agree with me.He didnt come
14、to the party,otherwise I might have seen him.butorotherwise34.7 Replacing ifIf can be replaced by words or expressions with a similar meaning.He is sure to come unless he has some urgent business.In case(that)he comes,let me know.I shall give you my dictionary on condition that you return it tomorro
15、w.I will go,providing/provided(that)my expenses are paid.(granted/granting that)Suppose/Supposing(that)he does not come,what shall we do?(assume/assuming that)I will cooperate as long as I am notified on time.Exercise 6 TranslationWhat is questioned is whether a country like Britain has a chance,ass
16、uming it has the will,to succeed where so many have failed,and even assuming that it has,should make the tremendous effort and take substantial financial risk of trying to leap-frog into leadership in entirely new technology,or whether it should take the softer option of merely catching up with the
17、rest of the industrialized world.现在提出的问题是，像英国这样的国家，假如愿意的话，是否有可能在很多国家已经失败的方面获得成功。假如有这种可能，英国是否应尽最大的努力，冒重大财政风险，一步进入全新技术的前列，或者应该采取比较稳妥的选择，只是赶上其他工业国的步伐。34.8 Omitting ifIf can be omitted with the if-clause partially invertedHad the doctor been available,the child would have been saved.Should it rain tomor
18、row,we would stay at home.Were I to go to the moon some day,I could see the surface of the moon with my own eyes.34.9 if vs whenBoth if and when are used in Type I Conditional.Using if suggests that something happens less frequently.Using when suggests that something happens regularly.If I have a da
19、y off from work,I usually go to the beach.I rarely have days off from work.When I have a day off from work,I usually go to the beach.I regularly have days off from work.I would buy that computer when it were cheaper.Not Correct I would buy that computer if it were cheaper.Correct34.10 if vs in casei
20、n case of can be used to shorten an if-clause as shown below:If there is a fire,leave the room.In case of fire,leave the room.While if expresses a condition(1),in case is used to express a possibility(2).(1)I need painkillers if Im in severe pain.(2)I need painkillers in case Im in severe pain.The e
21、xpression just in case is used pretty much the same way.I got you a pizza just in case you were hungry.(I dont know whether you are hungry.)Quiz1.(If/When)I leave work,I usually go to the fitness center to work out.2.She hates TV.She thinks television is a waste of time.(If/When)she watches any tele
22、vision at all,it is usually a documentary or a news program.3.If I(have)_ enough money,I(go)_ on safari to Kenya.However,my bank account is empty!4.If you help me move tomorrow,I(treat)_ you to a dinner and a movie.5.If you were to help me move tomorrow,I(treat)_ you to a dinner and a movie.6.If Hea
23、ther spoke Chinese,she(translate)_ the email for you yesterday.hadwould gowill treatwould treatwould have translated1.do not rain,go for a picnic If it doesnt rain tomorrow,we shall go for a picnic.Please click here to next question!Please click here to next question!2.go on foot,late If you go to school on foot,youll be late.Please click here to next question!Please click here to next question!3.do not have breakfast,hungryIf you do not have breakfast,youll be hungry.Please click here to next question!Please click here to next question!