1、现在完成时不可与表示特定过去时间的副词连用。e.g.1、I(leave)Shanghaifor3daysago.IShanghaifor3days.2、Tom(catch)acoldyesterday.Tomfor3days.2、过去时只限于表示过去的动作本身,与现在的结果无关。e.g.Whendidhecome?Whenhashecome?3、现在完成时不与疑问副词when连用,而一般过去时则可以。e.g.Hehasboughtahouse.Heboughtahousefiveago.(√)(×)如:ago,lastweek,then,yesterday,justnow,amomentago等.现在完成时VS一般过去时现在完成时(三)现在完成时(三)现在完成时构成用法常用状语1.have+动词过去分词2.has+动词过去分词1.have+动词过去分词2.has+动词过去分词表示某一动作或状态从过去某一时间一直持续到现在表示某一动作或状态从过去某一时间一直持续到现在for+一段时间since+过去某一时间for+一段时间since+过去某一时间现在完成时(have/has+v-ed)1.表示刚刚结束的动作,常和already,just,yet,now,notyet等连用.2.表示过去发生的动作对目前所造成的影响.3.表示经验经历,常和ever,never,often,always,once,twice,threetimes,before等连用.现在完成时(have/has+v-ed)4.表示从过去持续到现在的动作或状态,常和since+过去时,for+时间段,recently,lately,thesedays,thisweek,inthepastfewdays,duringthelasttwoweeks,sofar,uptonow,untilnow等连用.例如:(1)They’veknowneachothersince1995.(2)TonyhasstudiedChineseforayear.现在完成时(have/has+v-ed)5.区别:have/hasbeento表示去过某地,已经回来;have/hasgoneto表示去了某地,还未回来.例如:(1)BettyhasbeentoChina.SheknowsalotaboutChineseculture.(2)---Where’sMrYu?---HehasgonetoBeijing.Hewillbebackinaweek.现在完成时(have/has+v-ed)6.注意:当现在完成时跟表示持续的时间状语连用时,不能使用终止性动词.(1)Tomhascomefortwohours.(×)(2)Tomhasbeenherefortwohours.(√)下面我们来看看,如何把终止性动词转换成延续性动词.终止性动词转换成延续性动词becomebebuyhaveborrowkeepcatchacoldhaveacoldgettoknowknowputonwearleavebeawaydiebedeadarrivein/atbein/atcometobein/atjoinbeamemberof/beinstartbeonfinishbeoverhavebought-------havehadhaveleft------havebeenawayfromhaveborrowed-------havekepthavejoined------havebeeninhavecometo/gotto/reached/arrived(in/at)/movedto----havebeen(in)/havestayed(in/at)延续性动词---非延续性动词现在完成进行时表示过去已经开始,一直持续到现在的动作或状态。因为表示的是持续的动作或状态,所以使用的动词通常是延续性动词,时间状语通常由for或since引导.(非延续性动词不能直接和for或since连用)短暂性动词转延续性动词:borrowdiemarrycomebegintodobecomeclosekeepbedeadbemarriedbeheredobebeclosed短暂性动词转延续性动词:beginbuyfinishgoleavejoinopenbeonhavebeoverbetherebeawayfrombeinbeopen终止性动词转换成延续性动词Ibecameateacherin2001.Ibecameateacher7yearsago.Ihavebeenateachersince2001.Ihavebeenateacherfor7years.终止性动词转换成延续性动词Heboughtacomputerlastweek.Hehashadacomputersincelastweek.Hehashadacomputerforaweek.终止性动词转换成延续性动词SheborrowedabookinJuly.Sheborrowedabooktwomonthsago..ShehaskeptthebooksinceJuly.Shehaskeptthebookfortwomonths终止性动词转换成延续性动词Tomcaughtacoldyesterday.Tomhashadacoldsinceyesterday.Tomhashadacoldforaday.终止性动词转换成延续性动词BettygottoknowTonyin2001.BettymetTonyin2001..BettyhasknownTonysince2001.BettyhasknownTonyfor7years终止性动词转换成延续性动词Mybrotherputonhisglasseswhenhereadnewspapers.Mybrotherhaswornglassessince2005.Mybrotherhaswornglassesfor3years.终止性动词转换成延续性动词TheyleftthespacestationlastMonday.TheyhavebeenawayfromthespacestationsincelastMonday.Theyhavebeenawayfromthespacestationfortwodays.终止性动词转换成延续性动词Hisgrandfatherdiedin2004.His...