whenwhileassince引导时间状语从句的区别省公共课一等奖全国赛课获奖课件.pptx

when，while，as，since引导时间状语从句区分引导时间状语从句区分第1页一、when能够和延续性动词连用，也能够和短暂性动词连用；而while和as只能和延续性动词连用。Why do you want a new job when youve got such a good one already？（get为短暂性动词）你已经找到如此好工作，为何还想再找新？第2页 Why do you want a new job when youve got such a good one already？（get为短暂性动词）你已经找到如此好工作，为何还想再找新？The students took notes as they listened（listen为延续性动词）学生们边听课边做笔记。第3页 二、when从句谓语动词能够在主句谓语动作之前、之后或同时发生；while和as从句谓语动作必须是和主句谓语动作同时发生。第4页1从句动作在主句动作前发生，只用 when。When he had finished his homework，he took a short rest（finished先发生）当他完成作业后，他休息了一会儿。When I got to the airport，the guests had left（got to后发生）当我赶到飞机场时，客人们已经离开了。第5页2从句动作和主句动作同时发生，且从句从句动作为延续性动词时，when，while，as都可使用。When While As we were dancing，a stranger came in（dance为延续性动词）当我们跳舞时，一位陌生人走了进来。When While As she was making a phonecall，I was writing a letter（make为延续性动词）当她在打电话时，我正在写信。第6页3当主句、从句动作同时进行，从句动作时间概念淡化，而主要表示主句动作发生背景或条件时，只能用 as。这时，asas常表示常表示“伴随伴随”；“一一边边，一一边边”之意之意。As the time went on，the weather got worse（as表示“伴随”之意）第7页 The atmosphere gets thinner and thinner as the height increases 伴随高度增加，大气越来越稀薄。As years go by，China is getting stronger and richer 伴随时间一年一年过去，中国变得越来越富强了。The little girls sang as they went 小姑娘们一边走，一边唱。第8页4在未来时从句中，惯用when，且从句必须用普通时代替未来时。When the manager comes here for a visit next week，Ill talk with him about this下周，经理来这参观时，我会和他谈谈此事。第9页三、when用于表示“一就”句型中（指过去事情）。sbhad hardly/scarcely done sthwhenHardly Scarcely had sbdone sthwhen 第10页我刚一闭上眼，就有些人在敲门了。I had hardly scarcely closed my eyes when someone knocked at the doorHardly Scarcely had I closed my eyes when someone knocked at the door第11页四、since引导时间状语从句since引导时间状语从句 动词能够是延续性动词，也能够是终止性动词，都表示动作或状态结束，但汉语意思不一样，这点在了解时要尤其注意。第12页1若since引导状语从句谓语是终止性动词过去时，则从句表示时间是“从动作开始那一时刻起”。比如：He has studied very hard since he came to our school.自从他来到我们学校，他学习就非常努力。We have been missing them since they left here自从他们离开这里，我们就一直很想念他们。第13页 2若since引导状语从句谓语动词是连续性动词或表示状态动词过去时时，则从句表示时间是“从动作或状态结束时算起”。比如：I havent heard any noise since I slept.Sleep 为连续性动词，sleep动作结束时，即“醒来”时，所以这句应译为“我醒后还未听到任何声音”。It is three years since he was a teacher.第14页3若since引导状语从句谓语为连续性动词现在完成时，则表示动作和状态延续到现在（说话时刻），其表示时间起点应从动作发生之时算起。比如：I havent heard from him since he has lived there。这里has lived表示动作连续性，时间起点应从：“开始居住”时算起。所以此句可了解为“自从他（开始）住在那儿起，我就一直没收到他来信”。第15页五、Since在特殊句型中应用 句型句型I：“It is（has been）+时间+since+连续性动词过去时”，表示“自从以来到现在已经有多久。”比如：It has been quite some time since I was last in London.我上次离开伦敦至今颇有一段时间了。句型句型II：“It was+时间+since+连续性动词过去完成时”,表示“从到过去某时间点以来”。比如：It was three years since we had been here.那时我们在这已呆了三年。至于It is+一段时间+since句型与It has been+一段时间+since意思相同。前者是规范说法，后者是口语说法。第16页应注意是，在这种结构中，since引导从句绝对不能用否定式谓语动词来表示否定意义，下面两句都错了：It is a long time since he didnt study English.Its two months since you didnt come to see me.正确说法为：Its a long time since he studied English 他很久没学英语了。You havent come to see me for two months.你有两个月没来看我了。第17页延续性动词和短暂性动词延续性动词表示能够延续动作，这种动作能够延续下去或产生持久影响，又叫非点动词。常见这类动词有：study,work,stand,lie,know,walk,keep,have,wait,watch,sing,read,sleep,live,stay，smoke等。延续性动词使用方法很广，常见于现在完成时中句子中，且常与for，how，long，since等引导表示一段时间状语或状语从句连用。第18页终止性动词也称非延续性动词、瞬间动词或短暂性动词，表示不能延续动作，这种动作发生后马上结束。如open,close,finish,begin,come,go,arrive,reach,get to,leave,move,borrow,buy,die等。终止性动词又叫点动词，可用于现在完成时态，但因为动作是瞬时间完成所以不能与for或since引出时间状语连用。英语中常见非延续性动词在完成时态中可改为对应表示延续性动词或短语，这时可与表示一段时间状语连用。第19页