when-before-since区别及用法

when,before,since句型归纳1、when句型：(1)bedoingsth…when…Hewasstillsmilingwhenthedooropenedandhiswifecamein.他正笑着的时候门突然开了，他妻子走了进来。(2)beabouttodosth…when…Wewereabouttostartwhenitbegantorain.我们刚要出发，天就开始下雨了。(3)beonthepointofdoing…when正要…这时…Wewereontheponitofgivingupwhenatruckcameintooursight.我们正要放弃，这时看到了一辆卡车。(4)hardly/sceracely…when…(一…就…)Hehad/hardly/scarcelyfallenasleepwhenthetelephonerang.他刚要入睡电话就响了。(5)hadjustdone…when…(刚做完…某事发生)Ihadjustgonetobedafteraveryharddaywhenthephonerang.在劳累了一天之后我刚刚就寝，电话铃就响了。(6)还可以表示原因“既然”，相当于since;consideringthat.Itwasfoolishofyoutotakeataxiwhenyoucouldeasilywalkthereinfiveminutes.(4)hardly/sceracely…when…(一…就…)Hehadnot/hardly/scarcelyfallenasleepwhenthetelephonerang.他刚要入睡电话就响了。Wehadscarcelyarrivedwhenheaskedustoleave.我们才刚刚到他就叫我们走了.(1)beforesbcan/could…某人还没来得及……BeforeIcouldgetinaword，hehadmeasuredme．我还没来得及插话，他就给我量好了尺寸(2)Itwillbe/was+时间段+before过一段时间才……Itwillbe4yearsbeforehegraduates.他还有四年时间毕业了。Itwas5minutesbeforeheleft.过5分钟才离开2.before句型Itwon’tbelong……before….（从句用现在时）Itwasn'tlong……before….（从句用过去时）没过多久/用不了多久……就……eg:Itwasn'tlongbeforeifoundajob.Itwon'tbelongbeforeourcontrybecomesadevelopedcountry.我们国家很快就会成为一个发达国家。beforelong(adv.)不久，longbefore很久以前(3)haddone…before（才……）Wehadsailedfourdaysandfournightsbeforewesawland.我们航行了四天四夜才见到陆地。(4)hadnotdone---before---不到……就……Wehadn’trunamilebeforehefelttired.我们还没走到一英里路他就觉得累了。Itis/hasbeen＋时间段＋sincesb.did…§①§did动作为瞬间动词（非延续性），翻译为自从某事发生以来有多长时间Itis5yearssinceheleftBeijing.他离开北京5年了Ithasbeen3yearssincehecamebackfromabroad.自从他回国已经三年了3.since句型Itis/hasbeen＋时间段＋sincesb.did…§②§did动作为持续动词（延续性），翻译为自从不做某事有多长时间Ithasbeen5yearssincehewasastudent.他不当学生有5年了Itis5yearssincehelivedinbeijing.他不在北京居住有5年了3.since句型1.(04北京春)Wewereswimminginthelake______suddenlythestormstarted.A.whenB.whileC.untilD.before2.(02上海)Hewasabouttotellmethesecret______someonepattedhimontheshoulder.A.asB.untilC.whileD.when3.(05上海)Hetransplantedthelittletreetothegarden______itwasthebesttimeforit.A.whereB.whenC.thatD.until5.(06辽宁)Hewasabouthalfwaythroughhismeal______afamiliarvoicecametohisears.A.whyB.whereC.whenD.whileExercises:A.whenD.whenB.whenB.whenC.when6.(06天津)ThecostoflivinginGlasgowisamongthelowestinBritain,______thequalityoflifeisprobablyoneofthehighest.A.sinceB.whenC.asD.while7.(04年江苏)______Iacceptthatheisnotperfect,Idoactuallyliketheperson.A.WhileB.SinceC.BeforeD.UnlessD.A.8.______enteredtheofficewhenherealizedthathehadforgottenhisreport.A.HehardlyhadB.HadhehardlyC.HardlyhadheD.HardlyhehadC9.(03年北京)Hemadeamistake,butthenhecorrectedthesituation______itgotworse.A.untilB.whenC.beforeD.as10.(04福建)Scientistssayitmaybefiveorsixyears______itispossibletotestthismedicineonhumanpatients.A.sinceB.afterC.beforeD.when11.(06四川)－Whydidn’tyoutellhimaboutthemeeting?－Herushedoutoftheroom______Icouldsayaword.A.beforeB.untilC.whenD.after12.(05北京春)Itisalmostfiveyears______wesaweachotherlasttime.A.beforeB.sinceC.afterD.becauseCCAB