if和unless区别和练习

1/5Chapter1语法If和unless引导的条件状语从句我们用if引导的条件状语从句来讨论可能的条件以及该条件成立时可能的结果。一.学习if引导的条件状语从句的用法，我们可先从如下的口诀入手：If条件句不一般，几个要点记心间；条件句，放在前，逗号要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。Wecanwalkthereifwecan’tfindabus.如果我们找不到公车，也能走路去那里主句条件状语从句Ifitrainstomorrow,wewillnotgotothezoo.如果明天下雨，我们就不去动物园条件状语从句主句Whatwillyougoifyoufindsomeoneindanger?主句条件状语从句如果你发现某人有危险，你会怎么做？If条件句有不同的类型，简述如下：1.用if条件句表达客观真理或普通现象If条件句用于表达客观真理或普通现象时，主，从句时态均用一般现在时，如：Eg.Ifyoufreezewater,itturnsintoice.Afishdiesifyoutakeitoutofwater.2.用if条件句表示将来可能发生的事情在表示将来可能发生的事情的if条件句中，主句用一般将来时，而if从句用一般现在时表示将来的时间，即主将从现Eg.IfIlikethehouse,Iwillbuyit.如果我喜欢这房子，我就会把它买下IwilltellherifIseeher.如果我见到她，我就会告诉她。主句中的will也可以用情态动词can,may或might等代替。如：Eg.Iftheyarefriendly，Imightinvitethemtotheparty.如果他们很友善，我可能会请他们去参加聚会Ifwehurrynow,wecanstopforcoffeelater.如果我们现在抓紧时间，就可以稍后去喝咖啡2/5注意：在条件句中，主句部分只能使用动词will的一般将来时，不能使用begoingto的结构二.Unless的条件句表示在特定条件下，才决定做或不做一件事，中文用的连接词一般是“除非”和“否则”。如：除非刮台风，否则演唱会将如期进行。在英语中，我们可以用unless表达这个意思，相当于ifnot。以这个句子为例：Theconcertwillbeheldasscheduleunlessthereisatyphoon.=theconcertwillbeheldasscheduleifthereisnotatyphoonShewillkeeponsingingunlesssheistoldtostop.她会一直唱下去，除非有人叫她停止=shewillkeeponsingingifsheisnottoldtostop也可以用or(否则)来做同义句转换Unlessyoulistencarefully,youwon’tknowtheanswer.=ifyoudon’tlistencarefully,youwon’tknowtheanswer.=youshouldlistencarefully,oryouwon’tknowtheanswer.深圳中考题：1.IfI________hisphonenumber,Iwilltellyou.A.findB.foundC.willfindD.havefound2.Wewillgocampingifit_______tomorrow.A.Won’trainB.didn’trainC.doesn’trainD.isn’training3.I’mwaitingformyfriend.Ifhe_______,I______swimmingalone.A.doesn’tcome;willgoB.won’tcome;willgoC.willcome;won’tgoD.don’tcome;willgo4.______yougotothesupermarketat7p.m,youcanbuyalotofcheapfood.A.IfB.UnlessC.WhetherD.When5.Iwon’tgettothepartyontime______Icatchthefirsttraintomorrowmorning.A.IfB.UnlessC.WhetherD.When6.------Shallwegoonapicnicthisweekend?------Goodidea!Unlessit_______.A.rainsB.doesn’trainC.rainD.won’train3/57.-----CanIchangethejacketforanotherone______itdoesn’tfitmewell?-----Ofcourse.A.unlessB.ifC.thatD.though8.Nobodycanlearnmathswellheworkshardonit.AifBunlessCthoughtDhowever9.Iffishawayfromwater,theydie.Aaretaking,won’tBaretaken,willCarebeingtaken,willDtake,won’t10.Eachstudentcanaskteachersforhelpifhehowtoworkouttheproblem.AwillknowBwon’tknowCdon’tknowDdoesn’tknow练习:Awomanshouldneverbeseeneatingordrinking,unlessitbelobstersaladandChampagne,theonlytruefeminineandbecomingviands.LordByronIdon'tfeelrightunlessIhaveasporttoplayoratleastawaytoworkupasweat.HankAaronNogreatpoetry,ofwhateverkind,isconceivableunlessthesubjecthasbecomeintegratedwiththepoet'smindandmood.LascellesAbercrombieI'mnotgoingtojustsaynicethingsabouteverybodyunlessImeanit.F.MurrayAbrahamUnlessyou'rewillingtohaveago,failmiserably,andhaveanothergo,successwon'thappen.PhillipAdams1.IfI_____you,I____veryhappy.A.were,wouldbeB.am,shallbeC.were,shallbeD.am,wouldbe2.Ifhehadnotlosthismoney,he____thepianolastweek.A.wouldbuyB.hadboughtC.couldhaveboughtD.bought3.____Iknownit,Ishouldhavetoldhim.4/5A.HaveB.HadC.HavingD.If4.____theclouds,youwouldfindtheairplaneintheskyeasily.A.WereitnotforB.IfithadnotbeenforC.IfitwerenotD.Haditnotbeenfor5.IfIhadknownthat,I___so.A.wouldn’tdoB.won’tdoC.didn’tdoD.wouldn’thavedone6.Ifit___sohard,we’dgototown.A.isn’trainingB.weren’trainingC.doesn’trainD.isn’tgoingtorain1.答案A2答案C3.答案B4.答案A5.答案D6.答案B7.He_____youifyou____toseehimthatafternoon.A.mighttell,weregoingB.told,weregoingC.mighthavetold,hadgoneD.shouldtell,went8.Ifyouhadstartedsooner,you____there.A.mayhavegotB.mighthavegotC.shallhavegotD.musthavegot9.Ifweweretobe2ooyearsold,we____everything.A.willchangeB.canchangeC.couldchangeD.shallchange10.Idon’tthinkthatIshallfail,butifI___Iwouldtryagain.A.failB.wouldfailC.shouldfailD.hadfailed11.Ifyou____toseeMary,whatwouldyoutellher?A.areB.willbegoingC.mustD.were12.Ifthetrainleavesathalfpastten,there____notimetolose.5/5A.wouldB.isC.willD.has7.答案C8.答案B9.答案C10.答案C11.答案D12.答案Bunless…“除非，如果不……”(=if…not)[例句]wIshallgotomorrowunlessitrains.如果不下雨，我明天去。–ShallTomgoandplayfootball?–Notunlesshehasfinishedhishomework.除非他完成作业，否则不能出去。Iwon’tgounlesshecomestoinvitemehimself.w除非他本人来邀请我，不然我是不会去的。Iwon’tattendhisbirthdaypartyunlessinvited(=unlessIaminvited).除非被邀请，否则我不去参加的生日晚会。1.Themenwillhavetowaitallday______thedoctorworksfaster.（2001北京春季）A.ifB.unlessC.whetherD.that2.Youwillsucceedintheend_____yougiveuphalfway.（2001上海）A.evenifB.asthoughC.aslongasD.unless3.______youcallmetosayyou’renotcoming.I’llseeyouatthetheater.（2004吉林）A.ThoughB.WhetherC.UntilD.Unless