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Unit4PresentPerfectTense现在完成时态•have/has+过去分词PresentperfecttenseThestructureofthePresentPerfectTenseis:subjectaux.vmainv+IhaveseenET.+Youhaveeatenmine._ShehasnotbeentoRome._Wehavenotplayedfootball.?HaveyoufinishedIt??HashedoneIt?通常使用现在完成时的几种情况：•1表示发生在过去对现在仍有影响的动作。•Wehavealreadycleanedtheclassroom.•ThedisappearanceofJustinhasmadeKellyveryunhappy.•Ihavealreadyreadthebook.•Theboyhascomeback.2.表示一个刚刚完成的动作•TheyhavejustreturnedfromFrance.•3表示过去发生反复多次的动作。•ThecityisveryfamiliartomebecauseIhavevisitedittwice.•Youdon’tneedtodescribeher,forIhavemetherseveraltimes.•ThismonthIhavebeentoBeijingfor5times.常与twice,threetimes等连用4表示过去开始的动作或状态一直延续到现在表示动作只能用于某些带有延续意义的动词。•Shehastaughtheresincetenyearsago.•Since1949,Chinesepeoplehavelivedabetterlife.•Wehavebeeninthisschoolfor3months.•WehavelearnedEnglishfor10years.•瞬间动作要用否定式才能延续•Ihaven’tseenherfor3years.•Ihaven’tseenhersincelastyear.since+时间点for+时间段thesedaysrecentlysofarinthepastfewyearslatelybynow延续性与非延续性动词：•判断正误：•延续性动词常与for,howlong,since等引导的表示一段时间的状语或状语从句连用。•一些非延续性动词如come,go,leave,die,join,marry等用于现在完成时，一般不可以与表示一段时间的时间状语连用，此时应改为意义相近的延续性动词来表达。•1Hehasdiedfor3years.•2Hehasbeendeadfor3years.•3Hedied3yearsago.•4Ithasbeen3yearssincehedied.•5Howlonghaveyouborrowedit?FTTTFkept注意：非延续性动词的否定形式可以与表示延续时间的状语连用。即动作不发生的状态是可以持续的。判断正误：（）Ihavereceivedhisletterforamonth.（）Ireceivedthisletteramonthago.（）Ihaven'treceivedhisletterforalmostamonth.错对对•1.I’llgiveyouthebookassoonasI______________(finish)it.•2.Ifyou_____________(see)thefilm,youwilllikeit.•3.I’llgotothepartyassoonas(orwhen)I_____________(finish)myhomework.havefinishedhaveseen5.在时间或条件从句中表示在将来某个时间前要完成某个动作havefinished•1We_____________(study)Englishforaboutfiveyears.•2They______________(live)inthesouthsincetheirdaughterwasborn.•3I___________(read)yourarticlethreetimes.It’swellwritten.•4Thestudent_________________(finish)herhomeworkalready.•5Thepolice____________________(justfinish)searchingthearea.havestudiedhavelivedhavereadhasfinishedhavejustfinished•现在完成时的时间标志•1不表示具体或确定时间的一些状语往往可成为现在完成时的标志。•（1）already和yetalready一般用于肯定句中，yet一般用于否定句和疑问句中。•（2）ever和never多用于否定或疑问句中，表示“曾经”或“从未”等。•Haveyoueverseenanyaliensbyyourself?•Ihaveneverseenanyaliens.•(3)表示到说话为止的过去时间状语，如just，before，uptonow，thepastfewyears等。•Hehasbeentakenawaybyaliensbeforeandhestillhasnightmaresofthatnow.••(4)包括“现在”在内的时间状语。如：now,today,thismorning/month/year/term等。•Haveyoumethimthisterm?•No,Ihaven’t.•2.带有since或for等表示“一段时间”的状语。•Ihaven’tseenmymotherfortwoyearsandImissherverymuch.•关于现在完成时的几点补充：•（1）现在完成时常与since连用，表示“自……以来”,一直进行或者未进行某项活动，在since分句中，通常用非持续性动词的一般过去时，主句中的动词常用现在完成时，如果主句为表示时间长度的itbe句型，动词可用一般现在时代替现在完成时。•Itisthreemonthssincehewrotetome.•Itisthreemonthssincehewrotetome.•Itisthreemonthssincehewrotetome.2)在It/That/Thisisthefirsttime+(that)从句中,当主句谓语为is/willbe时,that从句中的动词用现在完成时.•ItisthefirsttimethatI’vebeenhere.•当主句动词为was时,that从句中的动词通常用过去完成时.•Itwasthefirsttimethisyearthathehadn’tworkedonSaturday.•这是我第一次上网冲浪ThisisthefirsttimethatIhavesurfedtheInternet.•1.---Doyouknowourtownatall?---No,thisisthefirsttimeI___here.•A.wasB.havebeen•C.cameD.amcomingB•2.---Haveyou___beentoourtownbefore?•---No,it'sthefirsttimeI__here.A.even,cameB.even,amcomingC.ever,comeD.ever,havecomeD3)先行词是最高级形式或被最高级形容词修饰时,定语从句常用现在完成时.•ThisisthebestfilmthatI’veseen.现在完成时与一般过去时的区别：•一般过去时表示发生在过去的动作，和现在无关；•现在完成时则强调某一发生在过去的动作与现在的关系，如对现在产生的结果或影响等。•He__________(work)inthecityfortenyears.workedhasworkedI_______(see)thisfilmyesterday.（强调看的动作发）I____________(see)thisfilm.（强调对现在的影响，电影的内容已经知道了）He__________(be)intheLeagueforthreeyears.（他仍然是一名团员)He________(join)theLeaguethreeyearsago.（强调加入的动作发生在过去）sawhaveseenhasbeenjoined现在完成时与一般过去时常用的时间状语：•一般过去时常与具体的时间状语连用，•而现在完成时通常与模糊的时间状语连用，或无时间状语。•一般过去时的时间状语：•yesterday,lastweek，…ago,in1980,inOctober,inthepast等，皆为具体的时间状语。•现在完成时的时间状语：•for,since,already,yet,sofar,uptonow,ever,never,recently,lately,just,inthepast…years,等，皆为不确定的时间状语。一般过去时还是现在完成时？•1They_______(move)tothesouthin1990and________(live)theresincethen.•2Eric_______(leave)homelastyearand___________(justcome)back.•3Justin__________(be)awayfromhomeforseveraldays.He_____________(disappear)lastFriday.•4They_________(buy)thishousethreeyearsagoandthey__________(live)heresincethen.movedhavelivedlefthasjustcomehasbeendisappearedboughthavelivedMyfriendJackhasjustsentmeane-mail,tellingmeabouthistravelsaroundtheworld.He_______(justbe)toQomolangmaBaseCampand_______(see)aYetithere.Heisstillveryexcitedaboutit.He________(visit)thegreatPyramidinEgypttoo.Hesaysthathe_______(love)Egyptbuthe_______________(notvisit)allthepyramidsyet.He____________(swim)inLochNess,butluckilyhe______________(nevermeet)theLochNessMonster!He_____________(dive)intheIndiaOceanmanytimeslookingfortreasure.Althoughhe________(find)manysunkenships,he_____(notfind)anytreasure.______he________(be)totheGreatWallbefore?I’mnotsure-butIhave.hasjustbeensawhasvisitedloveshasn’tvisitedhasswumhasnevermethasdivedhasfoundhasn’tfoundHasbeen