when-before-since区别及用法课件.ppt

1、when,before,since句型归纳-精品-1、when 句型：句型：(1)be doing sthwhen He was still smiling when the door opened and his wife came in.他正笑着的时候门突然开了，他妻子走了进来。(2)be about to do sthwhen We were about to start when it began to rain.我们刚要出发，天就开始下雨了。(3)be on the point of doingwhen正要正要这时这时 We were on the ponit of giving u

2、p when a truck came into our sight.我们正要放弃，这时看到了一辆卡车。我们正要放弃，这时看到了一辆卡车。-精品-(4)hardly/sceracelywhen(一一就就)He had/hardly/scarcely fallen asleep when the telephone rang.他刚要入睡电话就响了。(5)had just done when(刚做完刚做完某事发生某事发生)I had just gone to bed after a very hard day when the phone rang.在劳累了一天之后我刚刚就寝，电话铃就响了。(6)

3、还可以表示原因还可以表示原因“既然既然”，相当于，相当于since;considering that.It was foolish of you to take a taxi when you could easily walk there in five minutes.-精品-(4)hardly/sceracelywhen(一一就就)He had not/hardly/scarcely fallen asleep when the telephone rang.他刚要入睡电话就响了。We had scarcely arrived when he asked us to leave.我们才刚

4、刚到他就叫我们走了.-精品-(1)before sb can/could 某人还没来得及某人还没来得及Before I could get in a word，he had measured me 我还没来得及插话，他就给我量好了尺寸我还没来得及插话，他就给我量好了尺寸(2)It will be/was+时间段时间段+before 过一段时间过一段时间才才 It will be 4 years before he graduates.(3)他还有四年时间毕业了。他还有四年时间毕业了。(4)It was 5 minutes before he left.过过5分钟才离分钟才离开开(5)2.bef

5、ore句型句型-精品-It wont be long before.（从句用现在时）（从句用现在时）It wasnt longbefore.（从句用过去时）（从句用过去时）没过多久没过多久/用不了多久用不了多久就就eg:It wasnt long before i found a job.It wont be long before our contry becomes a developed country.我们国家很快就会成为一个我们国家很快就会成为一个发达国家。发达国家。before long(adv.)不久，不久，long before 很久以前很久以前 -精品-(3)had done

6、 before （才（才）We had sailed four days and four nights before we saw land.我们航行了四天四夜才见到陆地。我们航行了四天四夜才见到陆地。(4)had not done-before-不到不到就就 We hadnt run a mile before he felt tired.我们还没走到一英里路他就觉得累了。我们还没走到一英里路他就觉得累了。-精品-It is/has been时间段时间段since sb.diddid动作为瞬间动词（非延续性），翻译动作为瞬间动词（非延续性），翻译为自从某事发生以来有多长时间为自从某事发生以

7、来有多长时间 It is 5 years since he left Beijing.他离开北京他离开北京5年了年了It has been 3 years since he came back from abroad.自从他回国已经三年了自从他回国已经三年了 3.since句型句型-精品-It is/has been时间段时间段since sb.diddid动作为持续动词（延续性），翻译为动作为持续动词（延续性），翻译为自从不做某事有多长时间自从不做某事有多长时间 It has been 5 years since he was a student.他不当学生有他不当学生有5年了年了It is

8、 5 years since he lived in beijing.他不在北京居住有他不在北京居住有5年了年了 3.since句型句型-精品-1.(04北京春)We were swimming in the lake _ suddenly the storm started.A.whenB.whileC.untilD.before2.(02上海)He was about to tell me the secret _ someone patted him on the shoulder.A.as B.untilC.whileD.when3.(05上海)He transplanted the

9、little tree to the garden _ it was the best time for it.A.whereB.when C.thatD.until5.(06辽宁)He was about halfway through his meal _ a familiar voice came to his ears.A.why B.where C.when D.whileExercises:A.whenD.whenB.whenB.whenC.when-精品-6.(06天津)The cost of living in Glasgow is among the lowest in Br

10、itain,_ the quality of life is probably one of the highest.A.since B.when C.as D.while7.(04年江苏)_ I accept that he is not perfect,I do actually like the person.A.While B.Since C.Before D.Unless D.A.8._ entered the office when he realized that he had forgotten his report.A.He hardly had B.Had he hardl

11、y C.Hardly had heD.Hardly he had C-精品-9.(03年北京)He made a mistake,but then he corrected the situation _ it got worse.A.untilB.whenC.beforeD.as10.(04福建)Scientists say it may be five or six years _ it is possible to test this medicine on human patients.A.sinceB.afterC.beforeD.when11.(06四川)Why didnt you tell him about the meeting?He rushed out of the room _ I could say a word.A.beforeB.untilC.whenD.after12.(05北京春)It is almost five years _ we saw each other last time.A.beforeB.sinceC.afterD.because CCAB-精品-