时间状语从句课件.ppt
while,when,before,after,as soon as,since,until 引导时间状语从句的用法,1.while 的用法(1).引导时间状语从句，意为“当时 候”“在期间”。His parents died while he was at school.在他上学期间他父母去世了。(2).引导时间状语从句，意为“与同时”。You may go swimming while Im having lunch.我吃午饭的时间里你可以去游泳。,时间状语从句,Grammar,引导时间状语从句：at/during/after the time that 在/当时；在之后I loved math when I was at school.我在学校时喜欢数学。He looked aside when I spoke to him.我对他说话的时候，他向旁边看。,2.when的用法,while,when用法辨析：,(1).while引导时间状语从句作“当时候”讲时，只能与延续性动词连用。(2).when引导时间状语从句作“当时候”讲时，既可与延续性动词也可与瞬间动词连用。While he was reading,he fell asleep.他在读书的时候睡着了。When he came in,I was having lunch.他来时我正在吃午饭。,3.before 的用法,(1).before 用作连词，其基本词义是“在-之 前”，用来表示时间或顺序。如：Turn the light off before you sleep.睡前先把灯熄掉.Think before you speak.说话之前应先想清楚.但在不同的语境中before 有不同的翻译,4.after的用法 在之后,(1).prep.After testing,some students look very happy.考试结束后，一些学生看起来很高兴。,(2).adv.It happened twenty years after.这事发生在20年之后。,(3).conj.we all missed you after you left.你走了以后，我们都很想你,5.as soon as 的用法,as soon as连接的时间状语从句中，指未发的动作，规律是：主句一般将来时，从句用一般现在时代替一般将来时(主将从现)如：I will tell him the news as soon as he comes back。他一回来我就把这个消息告诉他。指紧接着发生的两个短动作，主从句都用一般过去时He took out his English books as soon as he sat down.他一坐下就拿出了他的英语书。,6.since 的用法,since作连词引导时间状语从句的用法(1).若since引导的状语从句的谓语动词是终止性的过去时，则从句表示的时间是“从动作开始的那一时刻起”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。,(2).若since引导的状语从句的谓语动词是持续性动词或表示状态的动词的过去时时，则从句表示的时间是“从那持续动作结束或状态结束时算起”。I havent heard any noise since I slept.sleep 为持续性动词，sleep的动作结束时，即“醒来”我醒后还未听到任何声音。I have not heard from him since I lived in Shanghai.自从我离开(没住在)上海，就再也没有收到他的信。,(3).若since引导的状语从句的谓语为持续性动词的现在完成时，则表示从动作和状态发生延续到现在（说话时刻）。I havent heard from him since he has lived there。自从他（开始）住在那儿起，我就一直没收到他的来信。这里has lived表示动作的持续性，时间的起点应从：“开始居住”时算起。,7.until的用法,(1).介词until 表示“直到某一时刻;直到发生某事”用于肯定句中：ItmaylastuntilFriday.这可能要延续到星期五。Hewillbeworkinguntil5oclock.他将一直工作到五点钟。until用于肯定句中，表示句子的动作一直持续到until短语所表示的时间为止，即表示动作的终点。一般可译为“直到时(为止)”或“在以前”。,(2).连词until 表示“(直到时为止)”,用于肯定句中Continueinthisdirectionuntilyouseeasign.一直朝着这个方向走就会看见指示牌了。一般可译为“直到.为止”。在这种用法中，主句的谓语动词必须是持续动词(非瞬间动词)，如live,wait,last,love,like,stay,work,continue等,用于否定句中：Ihadnt know shewasforeignuntilshespoke.她不说话我还一直不知道她是个外国人。作连词的until用于否定句中，从句先发生，主句再发生。一般可译为“直到才。,二.单项选择1.A scientist must practice a lot _he can use all data tools well.A.as soon as B.when C.until D.before2._ she realized what was happening,she was hit over the head.A.When B.Before C.Since D.As,B,D,3.why didnt you help the little boy?-Oh,sorry.He had struggled to his feet_ I ran over.A.until B.after C.before D.since4.He made a mistake,but then he corrected the situation _it got worse.A.until B.when C.before D.as,C,C,5.Scientists say it may be 5 years_ it is possible to test this medicine on human patients.A.Since B.after C.before D.when6.Someone called me up in the middle of the night,but they hung up _ I could answer the phone.A.as B.since C.while D.before,C,D,7.Youd better give it up _ it is too late as its very dangerous.A.before B.as C.when D.since8.It would be months _ he was fit for work.A.until B.since C.before D.after,A,C,9.It was evening _ we reached the little town of Winchester.A.that B.until C.since D.before10.The scientists had tried out many kinds of chemicals _ they found the right one.A.since B.after C.before D.when,D,C,
