无私奉献while的区别

词·清平乐禁庭春昼，莺羽披新绣。百草巧求花下斗，只赌珠玑满斗。日晚却理残妆，御前闲舞霓裳。谁道腰肢窈窕，折旋笑得君王。M9U1othercountries,otherculturesPeriod4Grammarandusage---ByZhangAnzhongTeachingobjectives:TooverviewtheclausesandtheusageImportantanddifficultpoints:Howtouseclausescorrectly.Teachingprocedures:Step1.RevisionWhataresubordinateclauses•Whenanumberofideasarecombinedinonesentence,someideasaremoreimportantthanothers.Wecanusesubordinateclausestoexpresslessimportantideas.Thesecanbedividedintothreekinds:adverbial,nounorattributiveclauses.Step2.GrammarandUsageWhatareadverbialclauses?Adverbialclausescanexpresstime,place,manner,contract,condition,reason,purposeorresult.Theyareintroducedbyconjunctionsthatindicatethemeaningsoftheclause,e.g.,when,where,how,although,if,since,because,inorderthat,sothatCompletethefollowingwithproperconjunctions:AsIdidn’tknowtheway,Iaskedapoliceman.Ifitsnowstomorrow,wewillbuildasnowman.Hedidn’tgotoschooluntilhewaseleven.Wearrivedearly,sothatwegotgoodseats.WeintendtogoU.S.,evenifairfaresareexpensive.Difficultpointsas,when,while的区别1.____thedaywenton,theweathergotworse.(MET90)A.WithB.SinceC.WhileD.As2.Ihadjuststeppedoutofthebathroomandwasbusilydryingmyselfwithatowel_________Iheardthesteps.(湖南卷)A.whileB.whenC.sinceD.after3.-I'mgoingtothepostoffice.________you'rethere,canyougetmesomestamps?(NMET99)A.AsB.WhileC.BecauseD.Ifas,when,while都表示主、从句的动作或状态同时发生，但三者意义不尽相同。as和when引导的从句既可表示一点时间，也可表示一段时间，从句中的谓语动词既可以是持续性动词，也可以为短暂性动词，经常可以互换使用；while引导的从句通常表示一段时间，从句中宜用持续性动词作谓语。当从句中的谓语动词为持续性动词时，这三者可以通用.如：MotherwasworriedbecauselittleAlicewasill,especiallyas/when/whilefatherwasawayinFrance.妈妈担心，因为小艾丽思病了，特别是当父亲远在法国的时候。如果从句和主句要表示一个人的两个动作交替进行或同时完成时，则多用as，可译为“一边......，一边......”。例如：Helookedbehindfromtotimeashewent.他一边走，一边不时地往后看。Ithoughtofitjustasyouopenedyourmouth.你一张嘴我就知道你要说什么。（若表示两个短促动作几乎同时发生时，用as的场合多于when.）当主从句之间表示转折或对比关系时，多用while,不用as或when。如：ShethoughtIwastalkingaboutherdaughter,whileinfact,Iwastalkingaboutmydaughter.她以为我在谈论她女儿，而事实上，我在谈论我的女儿。如果表示从句的动作在主句的动作“之前”或“之后”发生时，多用when（=after）,不用as或while。此外，when还含有“atthatmoment”的意思（=andthen），引起的句子不能放在句首，也不能用as,while来替换。例如：Hewasabouttoleavewhenthetelephonerang.他正要离开，忽然电话铃响了。WewerewatchingTVwhensuddenlythelightswentout.我们正在看电视，突然灯灭了。1.Theyhadjustarrivedhomewhenitbegantorain.他们刚到家，天就开始下雨了。NotuntilIbegantowork____howmuchtimeIhadwasted.(NMET90)A.didn'tIrealizeB.didIrealizeC.Ididn'trealizeD.Irealized2.Notuntilallthefishdiedintheriver____howseriousthepollutionwas.(NMET95)A.didthevillagersrealizeB.thevillagersrealizedC.thevillagersdidrealizeD.didn'tthevillagersrealize3.Itwasnot___shetookoffherglasses____Irealizedshewasafamousstar.(MET92)A.when;thatB.until;thatC.until;whenD.when;then4.Itwasnotuntil1920___regularradiobroadcastsbegan.(NMET95)A.whileB.whichC.thatD.sinceuntil与till及not…until/till的用法until和till都可表示“直到．．．为止”，与持续性动词的肯定式连用。如：Hewaiteduntil/tillwefinishedourmeal.他一直等到我们吃完饭。当until和till表示“直到．．．才．．．”时，通常与短暂动词的否定式连用，这时，until和till也可用before代替。如：Ididn’tleaveuntil/till/beforeshecameback.直到她回来，我才离开的。(3)be动词肯定式和否定式都可以和until或till连用。(4)until引导的从句可以放在主句之前或主句之后，但till从句一般不放在句首。1.DidyouremembertogiveMarythemoneyyouowedher？-Yes，Igaveittoher____Isawher．（2001北京春招）A．whileB．themomentC．suddenlyD．once2.Ithoughtherniceandhonest________Imether.A.firsttimeB.forthefirsttimeC.thefirsttimeD.bythefirsttime有时，thetime（当……的时刻）,themoment（当……的时刻）,bythetime（到……时候为止）,nexttime(下次),thefirsttime(第一次……的时候),thelasttime(上次……的时候)，immediately（一……就……）,instantly（一……就……）,directly（一……就……）等词或词组以及hardly/scarcely…when…（刚……就……）,nosooner…than…（刚……就……）等关联词也可引导表示时间的状语从句。例如：1.Besuretocallonusnexttimeyoucometotown.下次你进城一定来看我们。2.Bythetimehewasfourteen,Einsteinhadlearnedadvancedmathematicsallbyhimself.爱因斯坦到十四岁时就自学完了高等数学。3.Sherushedintotheroomimmediately/themomentsheheardthenoise.她一听到这声音，就冲进房间。4.HeleftmeagoodimpressionthefirsttimeImethim.我第一次见他时，他给我留下了好印象。5.Hehadnosoonerarrivedtherethanhefellill.他刚到达那里就生起病来。6.Hehadhardlyfinishedwhensomeonerosetorefutehispoints.他还没全说完，就有人起来反驳他的论点。当hardly,scarcely,nosooner位于引起的句子的开头时，常用倒装语序。上面的例句可以依次改写成：Nosoonerhadhearrivedtherethanhefellill.Hardlyhadhefinishedwhensomeonerosetorefutehispoints.if和unless的用法1.TheWTOcannotliveuptoitsname________itdoesnotincludeacountrythatishometoonefifthofmankind.（2000全国）A．aslongasB．whileC．ifD．eventhough2.Themenwillhavetowaitallday____thedoctorworksfaster.（01北京春）A．ifB．unlessC．whetherD．Thatif和unless的用法一般情况下，unless相当于if…not，可以互换。如：Iwon’tletyouinunlessyoushowmeyourpass=Iwon’tletyouinifyoudon’tshowmeyourpass.（如果你不出示通行证，我就不让你进来。）但是，在下列情况下，两者是有区别的。unless引导真实条件句，if…not可以引导真实条件句或非真实条件句。unless从句中有否定词时，不能换成if…not结构。如果主句描述的是情感或情绪活动方面的内容，if…not结构不能换成unless。如：I’llbequitegladifshedoesn’tcomethisevening.(她今晚如果不来我很高兴。)unless表示唯一条件，不能用and连接重复使用，if…not则可以。because,since,as,for的区别1.Shewasill,______shedidn’tcometoschoolthismorning.A.sinceB.becauseC.asD.for2.Wehadbetterhurry____itisgettingdark．（MET1984）A．andB．butC．asD．unless3.TheItalianboywasregardedasahero____hegavehislifeforhiscountry．（MET85）A．accordingtoB．becauseofC．onaccountofD．becausebecause,since,as,for的区别1.在这四个连词中，because语气最强，它引导的从句表达的是未知的新信息，也是该主从复合句中的焦点，一般都置于主句之后（也可以放在主句之前，用逗号隔开）。在回答”