由 if 和unless 引导的条件状语从句

由if和unless引导的条件状语从句1.Ifweloseourshort-termmemory,weforgetthingshappeningrecently.译：______________________________________________________2.Ifthepictureissilly,strangeandcolorful,youwillrememberitbetter.译：______________________________________________________A:Ifsentences:actionswithdefiniteresults.有必然结果发生的行动eg:①Ifyougointoaclothesshop,youfindclothes.②Ifyougointoacarshowroom,youseecars.③Waterturnsintoiceifyoucoolit.④Thewoodfloatsifyouputitintowater.Conclusion:1).如果if条件句谈论的是重复发生和预示必定要发生的情景和事件，则主从句大多用一般现在时态。2).在if条件句中，if条件从句可以放在前面，也可以放在后面。当if引导的条件从句放在前面时，后面常用逗号隔开。B:Ifsentences:actionswithpossibleresults.有可能性结果发生的行动eg:Ifyouaskhim，hewillhelpyou．如果你请他帮忙，他会帮你的。Ifyoufailintheexam，youwilllethimdown．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及其产生的相关的结果，主句用一般将来时态，从句用一般现在时态。C:unless引导的条件状语从句：unless=if……not.conj.除非,若不,除非…（否则）e.g.:Let'sgooutforawalkunlessyouaretootired.=Ifyouarenottootied,let'sgooutforawalk.我们出去散步吧，除非是你太累。译：如果你不早点出发,你就不能及时赶到那儿。我们可以把unless或if…not从句放在句子开头或末尾。Youwillbelateforschoolunlessyouleavenow.=Unlessyouleavenow,youwillbelateforschool.除非你早点出发，（否则）你上学会迟到。Youwillbelateforschoolifyoudon’tleavenow.=Ifyoudon’tleavenow,youwillbelateforschool.如果你不早点出发，你上学迟到。“if”引导的条件状语从句的用法,现在总结一下:1)引导条件状语从句最常用的连词是if。if引导的条件句有真实条件句和非真实条件句两种（非真实条件句会在以后的虚拟语气中阐述），其引导的真实条件状语从句表示在某种条件下某事很可能发生。2）if条件句不一般,几个要点记心间;条件句,放在前,逗号要放句中间。条件句表可能，主句多用将来时；条件句表事实，主句常用现在时。【巩固练习】一．if和unless句型互改。Eg:Youwillfailtheexamifyoudon’tworkhard.=Youwillfailtheexamunlessyouworkhard.1）Unlessyouobeytherules,youwillbepunished.=________________________________________________.2)Afishdiesifyoudon’tkeepitinthewater.=________________________________________________3)NobodycanlearnEnglishwellifhedoesn’tworkhardonit.=________________________________________________.4)Unlessyoustartrightnow,youwillbelateforthemeeting.=________________________________________________.二．用if或unless填空。1.youputwoodintowater,itfloats.2.Isleepwiththewindowopenitisreallycold.3.Youwillnotimproveyourskillinashorttime__youpracticeplayingtheviolinregularly.4.Icemeltsyouheatit.5.youboilwater,itbecomessteam（蒸汽）.6.youdon’tworkhard,youwillfailtheexam.7.Hecan’tbehereontimehegetsupearly.8.youdon’thaveenoughsleep,youwillfeeltired.9.itisfinetomorrow,Iwillgofishingwithmydad.10.youfinishyourhomework,youwillnotgoouttoplay.三．单项选择。1.Youwillnotrememberthefactsyouunderstandthemwell.A.ifB.unlessC.ifnotD.because2.Shenzhenadirtyplaceifwetheground.A.is;litterB.willbe;willlitterC.is;arelitteringD.willbe;litter3.Ifyouharder,youwillfailtheexam.A.notworkB.workC.don’tworkD.won’twork4.youobeytherules,youwillbepunished.A.IfB.SinceC.BecauseD.Unless5.Hecan’tseethewordsontheboardunlesshehisglasses.A.wearB.wearsC.doesn’twearD.towear6.Ifyouplantseedsinsoil,.A.itgrowsB.theygrowC.yougrowD.itwillgrow7.Ifyoucheckyourtimetableeverynight,it__inyourmindbetter.A.willstayB.stayC.stayedD.staying8.AtouristwilleasilylosehiswayinBeijing______hehasamaporguide.A.ifB,becauseC.unlessD.when9.Ishalltelephonethepoliceandcomplainaboutit__thenoise.A.if,stopsB.unless,stopsC.ifnot,stopsD.unless,stop10.Isleepwiththewindowopenit’sreallycold.A.ifB.ifnotC.unlessD.until11.______youtry,youwillneversucceed.A.IfB.UntilC.SinceD.Unless12.______hedoesn’tcomeontime,wewillgowithouthim.A.IfB.UnlessC.WhenD.Because13.Iwillcometoseeyouifit______raintomorrowmorning.A.won’tB.didn’tC.doesn’tD.don’t14.Ifyoutakeafishoutofthewater,it______.A.dieB.diesC.willdieD.hasdied15.---ShallTonycomeandplaycomputergames?---No,_____hehasfinishedhishomework.A.whenB.ifC.unlessD.once