SectionAGrammarfocus4a—4b (11)

Revision,ThePresent,PerfectTense,1.现在完成时态表示过去发生的动作对现在造成的影响或结果Ourteacherhasleft.WehavestudiedEnglish.Ihavealreadyfinishedthehomework.Hehashadhislunch.Hehasbecomeadoctor.,构成,have/has+过去分词,2.某个动作从过去已经开始,一直持续到现在,还有可能持续到将来.动作的持续性要通过一段时间来表示.,一段时间的表达方法有两种:for:+一段时间forayearfortwoweeksforthreeyears,Since过去的某一时刻,sinceninesincelastweek一般过去时态的时间状语从句sinceyoucamesinceyougothome.,注意:for和since所引导的时间状语都表示一段时间.,Hehasbeenawaysincelastweek.,Hehasbeenawayforoneweek.,对划线部分提问都用Howlong,ThePastPerfectTenses,New,现在完成时：,助动词have/has+过去分词,过去完成时：,助动词had+过去分词,构成？,我认识他三年了。,Ihaveknownhimforthreeyears.,IhadknownhimwhenIwasastudent.,我当学生时，就已经认识他了。,hadknown,haveknown,was,我已经做完作业了。,表示在说话时已经做完。,Ihavefinishedmyhome-work.,在六点以前，我就已经完成作业了。,Bysixoclock,Ihadfinishedmyhomework.,表示在过去的某一段时间（sixoclock以前）已经做完作业，与现在无关。,他们已经吃过早饭了。,在他们到旅馆之前他们已经吃过早饭了。,Theyhavealreadyhadbreakfast.,Theyhadalreadyhadbreakfastbeforetheyarrivedatthehotel.,我从未看过如此令人兴奋的比赛,他说他从未看过如此令人兴奋的比赛。,Ihaveneverseensuchanexcitingmatchbefore!,Hesaidthathehadneverseensuchanexcitingmatchbefore!,过去完成时与现在完成时二者用法基本相同，但现在完成时以现在时间为基点，过去完成时则以过去的时间为基点，与现在无关，即过去的过去。过去完成时常用于宾语从句中;,Summary,用于由by,before等构成的短语引导的从句或者通过上下文表示。,Bythetimewegotthere,thebushadalreadygone.,Wegotthereat7:00,Thebusleftat6:59,WhenIgottothecheck-out,IrealizedIhadleftmypurseathome.,BeforeImether,Ihadheardalotabouther.,Before/When/Bythetime,+,过去时态,+,从句,过去完成时态,主句,bythetime（=when）,我们赶到学校时，已经上课了。,到时,_wegottoschool,theclass_already_,Bythetime,had,begun.,当我到达火车站时，火车已经开走了。,BythetimeI_tothestation,thetrain_already_.,got,had,left,到上学期末，我们共学1500个单词。,Bythe_of_termwe_1,500words,end,last,hadlearnt,当他到学校时，他意识到他把作业忘在家里了。,Whenhe_toschool,he_thathe_hishomeworkathome.,hadleft,got,realized,PuttheChineseintoEnglish,Shesaidthey_allthepreparation_Icame.,had,made,before,她说在我来之前她们已经做好了一切准备。,当我到达学校时，学生们都已经放学了。,School_been_bythetimeI_there.,had,over,got,当我迟到20分钟到机场时，他已经乘出租车去宾馆了。,He_ataxitothehotelwhenI_theairport20minuteslater.,hadtaken,gotto,在我进城以前，我们的汽车已经坏了，再也走不动了。,Beforewewentdown-town,ourcar_downandcouldntmove_.,hadbroken,anymore,当警察开始要抓他时，他已经携带家属去了加拿大.,He_toCanadawithhisfamilywhenthepolice_tocatchhim.,hadgone,began,当我昨天到达电影院时，电影已经开始了。,WhenIgottothecinemayesterday,thefilmhadalreadybegun.,他说他从来没读过如此有趣的故事。,Hesaidthathehadneverreadsuchaninterestingstory,这个法国人想起来他学过“cough”这个词。,TheFrenchmanrememberedthathehadlearnedtheword“cough”.,他记得他把钥匙放在房间里了,Hethoughthehadputhiskeyintheroom.,Whenhegothome,hismotherhadalreadygottosleep.,当