prefect全英解析

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1、presentperfectThe presentperfect isformedfromthepresenttenseoftheverb have andthe pastparticiple ofaverb:Thepresentperfect continuous isformedwith have/hasbeen andthe -ing formoftheverb:UseWeusethepresentperfecttense:·forsomethingthatstartedinthe past a

2、nd continues inthe present:They’vebeenmarried fornearlyfiftyyears.She haslived inLiverpool allherlife.Note: Wenormallyusethepresentperfectcontinuousforthis:She hasbeenliving inLiverpoolallherlife.It’sbeenraining forhours.· forsomethingwehavedone several

3、times inthe past and continue todo:I’veplayed theguitareversinceIwasateenager.He haswritten threebooksandheisworkingonanotherone.I’vebeenwatching thatprogrammeeveryweek.Weoftenuseaclausewith since toshow when something started inthepast:They’vebeenstayi

4、ng withus sincelastweek. I haveworked here sinceIleftschool.I’vebeenwatching thatprogrammeeveryweek sinceitstarted.·whenwearetalkingaboutour experienceuptothepresent:Note:Weoftenusetheadverb ever totalkaboutexperienceuptothepresent:Mylastbirthdaywasthew

5、orstdayI haveeverhad.Note:andweuseneverforthenegativeform:Haveyou ever met George?Yes,but I’ve never met hiswife.·forsomethingthathappenedinthepastbutisimportantatthetimeofspeaking:Ican’tgetinthehouse.I’velost mykeys.Teresaisn’tathome.Ithink shehasgone 

6、shopping.I’mtiredout.I’vebeenworking allday. Weusethepresentperfectof be whensomeonehas gone toaplaceand returned:A:Where haveyoubeen?B:I’ve justbeenouttothesupermarket.A: Haveyoueverbeento SanFrancisco?B:No,but I’vebeen toLosAngeles.Butwhensomeone hasn

7、otreturned weuse have/hasgone:A:WhereisMaria?Ihaven’tseenherforweeks. B: She's goneto Parisforaweek. She’llbebacktomorrow.Weoftenusethepresentperfectwith timeadverbials whichrefertothe recentpast:just;onlyjust;recently;Scientists have recently discovere

8、d anewbreedofmonkey. We have just got backfromourholidays.oradverbialswhich includethepresent:ever (inquestions); sofar; untilnow; uptonow; yet (inquestionsandnegatives)Haveyou ever seen aghost?Wherehaveyoubeen uptonow?Haveyoufin