Unit1Howcanwebecomegoodlearners?语法一.介词by的用法1.by意为“通过”，其后常接名词或动词-ing形式。用来表示“以、通过、用（某种方法或手段）”而达到某种预期的目的，常用来回答how引导的特殊疑问句。bydoingsth意为“通过做某事”—HowdoestheboyimprovehisspokenEnglish?—Bytalkingwithaforeigner.(1)—HowdoyoulearnEnglishsowell?—chattingwithmyuncleinAmericaonline.A.ByB.WithC.InD.And(2)JacksonstudiedChineseby__________tapes.A.listeningB.tolistenC.listeningtoD.tolisteningto2.by+时间，意为“不迟于，在……之前”Ihavetogotobedbyteno’clock.3.by+地点，意为“在……旁”Jimsatdownbythewindow.4.by+交通工具，意为“乘……”Igotoschoolbybike.5.由by构成的固定短语：bytheway顺便说一下byoneself独自=alone二.现在完成时的用法(一)用法:1.表示过去发生的某一动作或状态对现在造成的影响或结果.常用的标志词有already(“已经”,用于肯定句),yet(“还,已经”，用于否定句和疑问句),ever（“曾经”）,never（“绝不，从不”）,just（“刚刚”）,before（“以前”）,once（“一次”）,twice（“两次”）.Ihavealreadyeatenthedinner.（说明我现在饱了）。Ihavealreadyseenthefilm.(1)Youdon’tneedtodescribeher.I______herseveraltimes.A.meetB.willmeetC.havemet(2)—Hi,guys.Whereareyouheading(向……行进)now?—Home.Weallourmoney,sowehavetowalkhomenow.A.spendB.spentC.havespentD.arespending(3)Haveyoueverseenhim________?A.agoB.twodaysagoC.beforeD.justnow2.表示过去发生的某一动作或状态，一直持续到现在。经常与时间状语for+时间段,since+时间点或一般过去时从句,如：forfiveminutes（5分钟）since1985（自从1985年一直到现在）.sincehewasfiveyearsold（自从他是五岁的时候一直到现在）现在完成时的标志语还有sofar“到目前为止”注意：此时谓语动词要用延续性动词，若是非延续性动词要变成延续性动词。leave-beawayborrow-keepbuy-havebegin-beondie-bedeadjoin-beamemberofgo/come-beinopen-beopenbecome-beIhavewaitedforyouforthreehours.我一直等你等了三个小时。Hehasbeenawayforamonth.他已经离开一个月了。（hasbeenaway不能用hasleft）Herbrotherhasbeenamemberofarmyforthreeyears.（hasbeenamemberofarmy不能用hasjoinedarmy）HanMeihaskeptthebooksincelastweek.（haskept不能用hasborrowed）(1)Imyhometownforalongtime.Ireallymissit.A.leftB.wentawayfromC.haveleftD.havebeenawayfrom(2)—HowdoyoulikeyourEnglishteacher?—Heisgreat.Wealllovehim.Wefriendssincethreeyearsago.A.wereB.havemadeC.havebeenD.havebecome(3)—Anna,youChineseisgood.haveyoubeeninChina?—SinceIwasten.A.HowlongB.HowfarC.HowoftenD.Howsoon(4)Hasthemoviebegun?Yes,it____forfiveminutes.A.hasbegunB.beganC.hasb