一般过去时、现在完成时与一般现在时的区别

现在完成时与一般过去时、一般现在时的区别（一）一般过去时态、现在完成时态、一般现在时的概念一般过去时表示在过去某个时间发生的动作或存在的状态，也表示过去经常或反复发生的动作，常与yesterday、yesterdayafternoon、thedaybeforeyesterday、lastyear、in1965、amomentago、justnow等表示过去的具体的时间状语连用。例如：Hecamehereyesterday.•现在完成时表示过去的动作（或状态）对现在产生的影响和结果．常与ever，never，before,twice,already,just，yet，sofar，since,for，uptonow，inpastyears等，皆不确定或模糊的时间状语连用。•例如Hehasjustbrokenhisbottle.•一般现在时表示经常性，习惯性的动作或存在的状态.通常与副词sometimes,often,usually,always,everyday(year,month),once(twice,threetimes)aday,等时间状语连用。Theyusuallygotoschoolbybike.Itakethemedicinethreetimesaday.Shehelpshermotheronceaweek.HeoftenwatchesTv.MarylikesreadinginterestingstoriesMary’sfatherisapoliceman.Thereare50studentsinmyclass.(二）一般过去时态、现在完成时和一般现在时的区别１）现在完成时是表示过去的动作与现在的联系，主要说明的是现在的情况和状态；而一般过去时则强调动作发生在过去某一时间，与现在不发生联系。一般现在时表示经常性，习惯性的动作或存在的状态.与过去没有关系。例如：Wehaven'tseenhimsincelastyear.我们自从去年以来一直未见到他（现在还未见到）Wedidn'tseehimlastyear.我们去年没见到他.（现在不一定未见到）Ioftenseehim.(现在经常见到)２）现在完成时表示从过去发生一直持续到现在（包括现在）的某个动作或状态，与现在有关的时间状语连用，一般过去时表示过去某一特定（与现在无关）的时间，与具体的表示过去的时间状语连用。例如：Hehaslivedheresincehewasborn.自他出生以来一直居住在这儿。（since自从…以来，与现在有关，说明他还居住在这儿。）LiuMeiwenttoseehergrandmotherlastnight.刘梅昨晚去看了他外婆。（只说明昨晚）•例如：Wearegoodfriends(现在情况)•我们是好朋友。•Igottoknowhimin2005.(过去的动作)•我在2005年认识（结识）他•Wehaveknowneachothersince2005.(现在完成时把过去的动作和现在联系起来并着眼于现在)•自从2005年来我们就相互认识。（三）值得注意几个问题１）动作发生在过去，一直持续到说话的时候，并且还在延续时，要用现在完成时。例如：WehavestudiedEnglishfortwoyears.我们学英语两年了２）指过去的经历，但没有表示过去的时间状语，要用现在完成时。例如：IhavebeentoShanghaitwice.我曾去过上海两次．３）句子中如有过去时的时间副词（如yesterday,lastweek,in1960）时,不能使用现在完成时，要用过去时。Tomwrotealettertohisparentslastnight.4）以When开头的特殊疑问句，要用一般过去时。例如：Whendidyouloseyourpen?你什么时候丢了钢笔？5）just(刚刚）与现在完成时连用，justnow(刚才）与一般过去时连用。例如：Thetrainhasjustgone.火车刚刚离开。Thetrainleftherejustnow.火车是刚才离开。6）since作介词，后面跟时间名词一起作状语时，句子要用现在完成时；since作连词，引导状语从句时，主句用现在完成时，从句用一般过去时。7）sofar，inthelast/past……与现在完成时连用。例如：Sofar，manycountrieshavesentupsatellitesintospace.Inthelast30years，ourliveshavechangedalot.Hehasworkedinthisfactorysince1996.Ihaveknownhimsincehewasachild.(四）现在完成时应注意的四个区别1）延续性动词与短暂性动词的区别。2）since和for的区别。3）have/hasgoneto；have/hasbeento；have/hasbeenin的区别。4)already和yet的区别A、leave—beenawayfrombuy—haveborrow—keepdie—bedeadgetup—beupturnon—beoncome/getback—bebackgototown—beintownfinish—beovercatchacold—haveacoldclose—beclosed/notopenopen—beopenfallill/asleep—beill/asleepbegin/start—beonget/receivealetterfrom—havealetterfromB、cometo—behere/therearrivein（at）/getto/reach——behere/therejointheArmy-------beintheArmy/beasoldierjointheLeague-----beintheLeague/bealeaguemember（五）延续性动词和短暂性动词转换归纳1.Hedied10yearsago.---He____________for10years/since10yearsago.2.Heborrowedthebook2weeksago.---He________thebookfor2weeks.3.Heboughtthemotorbikeamonthago.---He________themotorbikeforamonth.4.Hearrivedherethreedaysago.---He________heresincethreedaysago.5.Theyturnedonthelight2hoursago.---Thelight____________for2hours.6.Helefthere2yearsago.---He____________fromherefor2years.7.Thefilmbegan30minutesago.---Thefilm____________for30minutes.8.Theyopenedthedooranhourago.---Thedoor____________foranhour.9.Theyclosedthedooranhourago.---Thedoor____________foranhour.10.Hejoinedthearmylastyear.---He________a____forayear.---He____________thearmyforayear.---It____ayear____hejoinedthearmy.延续性动词和瞬间性动词之间的转化1.Hedied10yearsago.---Hehasbeendeadfor10years/since10yearsago.2.Heborrowedthebook2weeksago.---Hehaskeptthebookfor2weeks.3.Heboughtthemotorbikeamonthago.---Hehashadthemotorbikeforamonth.4.Hearrivedherethreedaysago.---Hehasbeenheresincethreedaysago.5.Theyturnedonthelight2hoursago.---Thelighthasbeenonfor2hours.6.Helefthere2yearsago.---Hehasbeenawayfromherefor2years.7.Thefilmbegan30minutesago.---Thefilmhasbeenonfor30minutes.8.Theyopenedthedooranhourago.---Thedoorhasbeenopenforanhour.9.Theyclosedthedooranhourago.---Thedoorhasbeenclosedforanhour.10.Hejoinedthearmylastyear.---Hehasbeenasoldierforayear.---Hehasbeeninthearmyforayear.---Itisayearsincehejoinedthearmy.延续性动词和瞬间性动词之间的转化(keys)•for和since的运用since表“自从……以来”。•1)since+时间点•Hehasstayedheresince5o’clock.•2)since+时间段+ago•Hehasstayedheresince5hoursago.•3)since+从句•ShehastaughtEnglishsincehecame•here.••for+时间段•Hehaskeptthebookfor2weeks.•例如：•for:(长达）•1.Hehasstayedherefor3hours.•2.Hehasstayedheresince3hoursago.3.Hehasstayedheresince3o’clock.•4.HehastaughtEnglishsincehecamehere.Fillintheblankswith“for”or“since”:1.Wehavehadthenewcomputer_______aweek.2.HowlonghaveyoustudiedEnglish?IhavestudiedEnglish_______Iwasfive.3.Howlonghashetaughtinthisschool?Hehastaughtinthisschool______1998.4.Howlonghaveyouknowneachother?Wehaveknowneachother______overtenyears.5.Howlonghaveyoukeptyourpetdog?Ihavekeptit______twoyearsago.Ihavekeptit______twoyears.sincesinceforsinceforfor•JameshasbeeninCanada______Monday.•JameshasbeeninCanada______fourdays.•JamescametoCanadafourdays_____.•MyaunthaslivedinBrazil_____15years.•MyauntmovedtoBrazil15years_____.•ShehaslivedinBrazil______15years______.•Mikehasbeeninhospital_______October.•Mikehasbeeninhospital______twomonths•Mikecametothehospitaltwomonths______•Hehasbeeninhospital______twomonths___填上since,for或者ago.sinceforagoforagosin