1、Grammar:adverbial clause of time时间状语从句。I.when,while,as 可引导When I was walking down the street,I came acrossan old friend of mine.While he was in prison,he wrote his first novel.如果主句表示的是短暂动作，从句用进行时或延续性动作状态时,when,while,as可互换。II.区别1.as多用于口语中，引导持续性动作，侧重于两个动作同时发生,有“当 的时候”，“一边一边”或表示“随着”的含义,eg.He hurried ho
2、me,looking behind as he went.As time went on,Einsteins theory proved to be correct.As he grew older,he began to go deaf.2.while常引导延续性动作，表示的是一段时间,不是一点时间,强调动作同时发生，相当于during the time.Please dont talk so loud while others are talking.3.when 强调“特定时间”,从句动作发生与主句动作之前时用when，不可用while和as。while还有对比的含义,有时也表示“尽管”
3、，引导让步状语He likes pop music,while I am fond of folk music.I can have a rest when I have finished my work.All the lights went out when the clock struck twelve.when还可做并列连词,意为“那时,这时”,相当于and at this/that timeWe are about to set off on our way when it suddenlybegan to rain.I was walking on the street when
4、I saw a tailors shop.I had walked 20 miles when it started to rain.as,while,when 用法总结1.都可以引导时间状语，且意思为“当的时候”但as和2.while常强调两个动作同时发生。当强调两个动作时间3.先后时只能用when。2.when还可做并列连词,意为“那时,这时”,相当于and at this/that time。且还可用于“hardly/scarcelywhen”结构中，意为“刚就”。3.while 有时表示转折或引导让步状语，意为“然而”或 “尽管”。4.as 用法很多，引导时间状语时有时意为“一边一边”
5、或“随着”。也可做关系代词用与定语从句中，还可意为 “尽管”“因为”“按照”等，引导让步、原因、方式等状语从句。Grammar 2:past perfect tense过去的两个动作，如果一个动作发生在另一个动作之前，发生在前的就用过去完成时，即“过去的过去”。eg.When he reached the shop,it had already closed.1.在by,by the end of,by the time 后接某一表示过去的时间时。He had copied the report three times by ten lastnight.By the end of last F
6、riday,the project had already been completed.We had hoped to catch the 8:00 bus,but found it gone.3.no soonerthan.,hardly/scarcelywhen.中，前面用完成时，表示“刚就”/“一.就.”They had hardly been seated when the bus started.I had no sooner finished the work than the light went out.I had scarcely closed the window whe
7、n the storm came.I had thought he had died.2.表示原计划打算做某事而没有办成。常用词有:want,mean,plan,hope think,suppose,expect etc.此句式可以变成倒装，时态不变。Hardly had they been seated when the bus started.No sooner had I finished the work than the light went out.4.在有before and after 的时间状语从句中，因为有了明确的前后关系，主句可以用一般过去时代替过去完成时。The tra
8、in left before he got there.I played computer games after I(had)finished my homework.Exercises:1.He was about to tell me the secret _someone2.patted him on the should.A.As B.until C.while D.when2.I arrived late;I _ the road to be so icy.A.wouldnt expect B.havent expectedB.C.hadnt expected D.wasnt ex
9、pectingDC3._ modeling business is by no means easy to get into,the good model will always be in demand.A.While B.Since C.As D.IfA4.I will go home _ I have finished my homework.A.until B.when C.as D.while5.By the end of last year,another new hospital _.A.would be completed B.was being completed C.has
10、 been completed D.had been completedBD6.Helen _ her key in the office so she had to wait until her husband _ home.A.has left;comes B.left;had come C.had left;came D.had left;would come7.Mother was worried because little Alice was ill,especially _ father was away in Paris.A.as B.that C.during D.if CA
11、8.John and I _ friends for 8 years.We first got to know each other at a Christmas party.But we _ each other a couple of times before that.A.had been;have seen B.have been;have seen C.had been;had seen D.have been;had seen9.The new bridge _ by the end of this month.A.has been designed B.had been desi
12、gned C.is designed D.will have been designed10._exercise I,we went to do another exercise.A.Having finished B.Finishing C.After finished D.When finishingDDA11.-What was the party like?-Wonderful.Its years _ I enjoyed myself so much.A.after B.before C.when D.since12.-Can I join your club,Dad?-You can
13、 when you _ a bit older.A.get B.will get C.are getting D.will have got13.-How long has this bookshop been in business?-_ 1932.A.After B.In C.From D.Since DAD14._ you received the news?A.When was it that B.When was it C.When it was that D.When it was15.At this time tomorrow _ over the Atlantic.A.were
14、 going to fly B.well be flying C.well fly D.were to fly16.-What were you doing when I phoned you yesterday evening?-I _ my homework and was starting to take a bath.A.had just finished B.was finishing C.have already finished D.was going to finishABA16.The rest of money _ spent so far.A.was B.have been C.has been D.had been17.-Did you remember to give Mary the money you owed her?-Yes,I gave it to her _ I saw her.A.while B.the moment C.suddenly D.once18.Unfortunately when I arrived she_,so we only had time for a few words.A.just left B.has just left C.was just leaving D.had just left CBC
