if条件状语从句课件好用.ppt

If sentencesIf 引导的条件状语从句引导的条件状语从句If you cool water,it turns into ice.if clause从句从句main clause主句主句1.If you heat metal,it melts.如果把金属加热，它就会融化如果把金属加热，它就会融化。2.Water turns into ice if you cool it.如果你冷却水，它就会变成冰如果你冷却水，它就会变成冰。if clause从句从句main clause主句主句从句从句主句主句从句从句主句主句从句在主句前时，从句在主句前时，_ （用（用/不用）逗号隔开不用）逗号隔开当主句在前时，则当主句在前时，则_（用（用/不用）逗号不用）逗号不用用If you drop a glass,it breaks.If you heat ice,it melts.If you stand in the rain,you get wet.主句和从句都用主句和从句都用_(时态时态)因为因为if引导的条件句说的是引导的条件句说的是_一般现在时一般现在时客观事实客观事实/普遍现象普遍现象Actionswithdefiniteresults读下列例句，试着自己总结读下列例句，试着自己总结if 的用法：的用法：1.If you heat metal,it melts.如果把如果把金属加热金属加热，它就会融化，它就会融化。2.Water turns into ice if you cool it.如果你冷却水，它就会变成冰如果你冷却水，它就会变成冰。3.If you stand in the rain,you get wet.如果你站在雨里，就会淋湿。如果你站在雨里，就会淋湿。4.If you drop a glass,it breaks.如果你把玻璃杯掉在地上，它就会碎。如果你把玻璃杯掉在地上，它就会碎。由例句我们可以知道：如果if引导的条件句谈论的是一种_时，主句谓语动词便不用shall/will+动词原形，而直接用_时的动词形式。真理真理/客观事实客观事实一般现在一般现在Water _(turn)into ice if you Water _(turn)into ice if you _(cool)it._(cool)it.If you _(stand)in the rain,If you _(stand)in the rain,you _(get)wet.you _(get)wet.turnscoolstandget1.-b2.-d3.-g4.-a5.-h6.-c7.-f8.-e1.If you _water.2.A balloon _ it.3.If you _water.4.Metal _it.5.Wood _water.6.A glass_ it.heat ice,it turns intobursts if you stick a pin into cool steam,it turns intomelts if you heatfloats if you put it intobreaks if you dropActionswithpossibleresults读下列例句，总结读下列例句，总结if 的用法：的用法：1.If he runs,hell get there in time.如果他跑步去，就会及时赶到那。如果他跑步去，就会及时赶到那。2.He will help you if you ask him.如果你请他帮忙，他会帮你的。如果你请他帮忙，他会帮你的。3.If you fail in the exam,you will let him down.如果你考试失败了，你会让他失望的如果你考试失败了，你会让他失望的4.If you get up late,you will be late for school.如果你起床晚了，上课就会迟到。如果你起床晚了，上课就会迟到。由例句我们可以知道：在if引导的条件状语从句中，如果从句谈论的是一个有可能发生的事实有可能发生的事实以其产生的相关结果，从句用_,主句用_.一般现在时态一般现在时态一般将来时态一般将来时态(主将从现主将从现)I _(stay)at home if it _ I _(stay)at home if it _(rain)tomorrow.(rain)tomorrow.If he _(not come),I If he _(not come),I _(go)swimming alone.(go)swimming alone.will stayrainsdoesnt comewill goIf you get up late,you will be late for school.Look and sayget up latelate for schoolIf the telephone rings,I will answer it.Look and sayringanswerIf I have a lot of money,I will buy a big house.Look and saya lot of moneya big househard-workingIf she is hard-working,she will get good grades.get good gradesLook and saygo fishing.If it is sunny this Sunday,Ill go fishing.Look and saysunny this SundayP105BWilliamhasfiveproblemsGivehimsomeadvicefromcolumnAandB1Isometimesforgettotaketherightbooktoschool.Ifyoucheckyourtimetableeverynight,youllknowwhichbookstotake.一一、判断正、判断正误，如果有误误，如果有误，请更正，请更正1.Ifyouwilldomoreexercisethissummer,youwillbeveryfit.2.Thecandleburns,ifyoulightit.will do do把逗号去掉把逗号去掉3.IwillbuildmanyschoolsforthepoorchildrenifIwinabilliondollars.4.Ifyoufreezewater,itwillturnintoice.5.Myunclevisitsthemuseumifhewillhavetime.正确正确will turn turnsvisits will visit,will have hasIf的两个意思:If:“如果如果”“是否是否”引导条件状语从句引导条件状语从句引导宾语从句引导宾语从句Idontknowif hewillcometomorrow.Iwillgotothecinemaif itdoesntrain.主现从现主现从现/主将从现主将从现if可用将来时可用将来时 Betty will visit the History Museum if it Betty will visit the History Museum if it _(rain)tomorrow._(rain)tomorrow.Ben wants to know if it_ Ben wants to know if it_(be)fine tomorrow.(be)fine tomorrow.If引导的条件状语从句不用将来时，意思为“如果”。If引导的宾语从句可以用将来时，意思为“是否”。doesnt rainwill be是否是否如如果果Exercises:1.He will help me with my maths if he _ free.A was B will be C would be D is2.I dont know_ he will come tomorrow._ he comes,Ill tell you.A if;Whether B whether;Whether C if;That D if;If3.Please tell her my telephone number if she _(want)to know.wantsDD4.Will you come and stay with us for a while if you _(finish)doing your homework?5.Wang doesnt know if there _(be)an English evening next week.6.Mike asked me if we _(ask)any questions the next class.7.We are going for picnic tomorrow.Ill call Wendy to make sure_.A why to start B when to start C what to start D which to startwould askfinishwill beB8.-Would you please tell me_ next?-Think it over.Youll find a good way.A when to do B how to do C what to do D where to do9.I dont know if my uncle _.If he _,I will be very happy.A comes;will come B will come;will come C comes;comes D will come;comes10.Either you or I _ going to Shanghai.Only one person may go there.A are B were C am D was CDC()11.Ifit_sunnytomorrow,I_boating.A.isgoB.willbe,goC.is,willgoD.willbe,willgo()12.-whatwillyoudoifit_tomorrow,-IllstayathomeandwatchTV.A.rainB.rainsC.willrainD.israiningCB()13.Ifhe_,I_himthetime.A.comes,tellB.willcome,willtellC.comes,willtellD.willcome,tell()14.Ifit_,it_cold.A.snows,willbeB.snows,isC.willsnow,willbeD.willsnow,is()15.Ifyou_astoneintowater,it_.A.put,sinksB.put,willsinkC.willput,sinksD.willput,willsinkCB A 11.He_(help)me with my 11.He_(help)me with my mathsmaths if he if he _(be)free._(be)free.12.I dont know if Jim _ tomorrow.12.I dont know if Jim _ tomorrow.If he _,I will be very glad.If he _,I will be very glad.(come)(come)13._(tell)her my telephone number if 13._(tell)her my telephone number if she _(want)to know.she _(want)to know.14.If it _(be)sunny tomorrow,I _ 14.If it _(be)sunny tomorrow,I _(go)boating.(go)boating.15.If you _(boil)water,it _ 15.If you _(boil)water,it _(turn)into steam.(turn)into steam.16.You can _(travel)around the 16.You can _(travel)around the world if you _(have)money.world if you _(have)money.will helpwill helpisiswill comewill comecomescomesTellTellwantswantsisiswill gowill goboilboilturnsturnstraveltravelhavehaveTranslatethefollowingsentences:1.如果你请他帮忙,他会帮你的。Ifyouaskhim,hewillhelpyou.2.如果你考试不及格,你会让他失望的。Ifyoufailintheexam,youwilllethimdown.3.如果你作业做完了就可以回家了。Ifyouhavefinishedthehomework，youcangohome4.如果熊陷入危险，它们就攻击人。Ifbearsareindanger,theyattackpeople.5.如果我早早地到那里，我就可以快点看病。IfIgetthereearly，Icanseethedoctorquickly.翻译下面句子。1.如果明天不下雨的话，我就和同学们去动物园。2.如果周六你去购物的话，我就去。If it doesnt rain tomorrow,I will go to the zoo with my classmates.I will go shopping on Saturday if you go.Test yourself3.如果可能的话，我就去火车站接你。4.如果你想减肥，就锻炼身体吧。If possible,Ill meet you at the railway station.Take some exercise if you want to be thinner/lose weight.Test yourself