assoonas…一…就…=directly/immediately/instantly…

　　=thesecond/theminute/themoment/theinstant…

　　Eg.Hecamearoundtoseemeassoonas/themoment/immediatelyhecheckedinthehotel.

　　他刚一入住宾馆就来看我.

　　Theyinformedusthenewsimmediately/directlytheygotit.

　　他们一得到消息就通知了我们.

　　Thepolicemancametothespotthemoment/theinstant/theminutesheheardoftheaccident.一听说事故,这位警察就到了现场.

　　2.….before….

　　(1).没来得及…就…

　　Therooffellbeforehehadtimetodashintotheroomtosavehisbaby.

　　他还没有来得及冲进房间把孩子就出来,房顶就塌了.

　　HeranoffbeforeIcouldstophim.

　　Tomygreatdisappointment,myfavoritesingerlefttheconcertbeforeIcouldhaveawordwithhim.

　　(2).过了多久才怎么样,动作进行到什么程度才怎样

　　Theywalkedaboutthirtymilestothewestbeforetheysawavillage.

　　Theyworkeddayandnightaboutthreedaysbeforeeverythingreturnedtonormal.

　　ThreeyearspassedbeforeIknewit.

　　3.Itwas+时间段+before….过了多久才….;

　　Itwasnotlongbefore…不久就…

　　Itwill(not)be+时间段+before…要过多久(不久)…..才…..

　　Eg.Itwasnotlongbeforehesensedthedangeroftheposition.

　　Itwasthreeyearsbeforehecameback.

　　Itwillbehalfayearbeforeyougraduatefromthisschool.

　　4.nosooner…than…=hardly…when…一…就….,刚刚…就…

　　Nosooner/hardly+过去完成时,than/when+一般过去时

　　如果nosooner,hardly位于句首,主句要倒装.

　　HehadhardlysatdowntohavearestwhenthedoorbellrangandincameAllan.

　　Nosoonerhadhegotoffthetrainthanhisdaughterrantowardshim.

　　Hardlyhadwearrivedwhenshestartedcryingtogohome.

　　5.once一旦….,表示时间和条件

　　Onceyouunderstandthisrule,youwillhavenofurtherdifficulty.

　　Onceyouhavedecidedtodosomething,youshoulddoitwell.

　　Onceyouenterthechemistrylab,youshouldfollowtheteacher’sinstructions.

　　6.since…自从….以来

　　Since引导的从句不论是延续性或非延续性动词,都表示的是动作或状态的完成或结束.

　　注意一下句子翻译:

　　SincehelivedinNanjing,Ihavenotheardfromhim.(=sinceheleftNanjing…)

　　自从他离开南京以来,我没有收到过他的信.

　　SinceshewasinYangzhou,shehaskeptintouchwithherformerfriends.(sincesheleftYangzhou…)

　　她离开扬州以来,一直同过去的朋友保持着联系.

　　对比:

　　1).Ihaveneverseenhimsincehewasill.

　　他病好后,我就再也没有见到他.

　　2).Ihaveneverseenhimsincehefellill.

　　他生病以后我就再也没有见过他.

　　Itis/(hasbeen)+时间段+since+过去式

　　Itis/hasbeentwoyearssincehisfatherdied.

　　=hisfatherhasbeendeadfortwoyears.=hisfatherdiedtwoyearsago.

　　他的父亲去世两年了.

　　Ithasbeen8yearssinceIgraduatedfromuniversity.

　　=Igraduatedfromuniversity8yearsago.

　　Itis3yearssincehesmoked.他三年不吸烟了.(即,从句动词延续性的,译成否定意义;从句动词非延续性的,译成肯定意义.)

　　Itis3yearssinceheleftschool.-----他毕业三年了.

　　7….until…直到…时候;not…until…直到…才…

　　Youaretostayhereuntil/tillyourmothercomesback.

　　Themeetingwasputoffuntilteno’clock.

　　NotuntilwewatchedtheEarthDayprogramonTVdidweknowmuchaboutglobalwarning.

　　=WedidnotknowmuchaboutglobalwarninguntilwewatchedtheEarthDayprogram.

　　=ItwasnotuntilwewatchedtheEarthDayprogramonTVthatweknewmuchaboutglobalwa