状语从句中“when while as soon as before”等引导词的区分.
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状语从句中“when while as soon as before”等引导词的区分.
状语从句中“when while as soon as before”等引导词的区分.
状语从句中“when while as soon as before”等引导词的区分.
when 作为从属连词,引导状语从句,表示多种语法意义:1.表示时间,意为“当……时;在……的时候”.A.在时间、条件等状语从句里,用一般现在时表示将来时;当需要表达将来完成的意义时,必须使用现在完成时来代替.如:( 1 ) When you see him,please say hello to him.见到他时,代我问他好.( 2 ) When you have finished your experiment,please tidy the lab and put everything back in the cupboards.当你们做完实验后,请把实验室整理好并把物品放回柜子中.B.表示过去发生的事情,在 when 引导的时间状语从句的主从复合句中,动作发生在先的用过去完成时,在后的用过去时.如:( 1 ) When I was in Japan,I bought some beautiful pearls.我在日本时,买了一些漂亮的珍珠.( 2 ) When I reached the station,the train had left.当我到达火车站时,火车已经开走了.2.表示前面的叙述所没有提到过的信息.它总是对所描述的事件予以引人注目的强调,意为“这时;突然”;当位于句末的分句具有引种用法时,大致有以下三种情况:A.when 分句前面的分句使用过去进行时.如:( 1 ) 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 ) I was thinking of this when I heard my name called.我正想着这件事时,突然听到有人叫我的名字.B.when 分句前面的分句使用 was (were) about to,was (were) on the point 等.如:( 1 ) We were about to start when it began to rain.我们刚要出发就开始下雨了.( 2 ) He was on the point of leaving when someone knocked at the door.他刚要走就有人敲门.C.when 分句之前的分句用过去完成时,其中 sb had hardly / scarcely /barely … when 已成为固定词组.如:( 1 ) We had hardly fallen asleep when the bell rang.我们刚刚入睡,铃声就响了起来.( 2 ) He had scarcely arrived when he had to leave again.他刚刚到达就又要离开了.3.表示条件,相当于 if ,引导条件状语从句.如:How can I get a job when I can't even read or write?如果我连读和写都不会,我怎么能找到工作呢?4.表示对比,主要有以下两种情况:A.相当于 whereas,while,since,意为“既然;然而”.如:( 1 ) How can I help them to understand when they won't listen to me?既然他们不愿听我的,我又怎么能帮助他们弄明白呢?( 2 ) They have only three copies when we need five.他们只有三本,而我们却需要五本.B.when 从句中使用虚拟语气,意为“本来……却……”.如:( 1 ) She paid when she could have entered free.本来可以免费入场,而她却付了款.( 2 ) She stopped trying when she might have succeeded next time.她本来下次有可能获得成功,但她却不再尝试了.( 3 ) They were gossiping,when they should have been working.他们本该工作,却在那里说别人的闲话.5.由 w hen 等引导的状语从句,如果主语与主句的主语一致或是 it ,谓语动词又含 be 动词时,主语和 be 动词常常被省略,就变成“ when + V-ing/ V-ed/ adj/ 介词词组”的结构.如:( 1 ) When in Rome,do as Romans do.入乡随俗.( 2 ) When (we are ) young,we are full of hope.年轻时,我们大家总是充满希望.( 3 ) Don't reach sideways when standing on a ladder.站在梯子上时,不要侧着身子去够东西.while (1)引导时间状语 1.We must strike while the iron is hot.趁热打铁.2.While she was listening to the radio,she fell asleep.她听着收音机睡着了.(2)引起让步状语从句,意思是“虽然…但是….”、“尽管…但是…”(多放于句首)1.While he loves his students,he is very strict with them..虽然他爱他的学生,可是他对他们很严格.2.While these experiments are interesting and useful,it is important to remember that they may not always tell us much.(BookIIIp125) 虽然这些实验很有趣也有用,但是很重要的是要记住,这些实验也可能不会告诉你很多.(3)引起条件状语,意思是“只要” 1.While there is life there is hope.只要生命存在,就有希望.2.While there is a way there is away.有志者事竟成.as soon as before as soon as连接的时间状语从句中,指未发生的动作,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 如:I will tell him the news as soon as he comes back.指紧接着发生的两个短动作,主从句都用一般过去时 如He took out his English books as soon as he sat down 就这两种情况 ,熟记就行.在宾语从句中,当主句为与过去时的时候,从句必须用与主句相对应的时态,所以为了与主句动词said呼应,时间状语从句中的will look up应该对应为过去将来时态would look up,finds对应为found