状语从句 状语从句在主从复合句中修饰主句中的动词,形容词或副词,按意义可分为时间、地点、原因、目的、结果、条件、方式、比较、让步等状语从句。 从句的位置放在句首,也可放在句末。放在句首时,从句后面常用一个逗号,放在句末时,从句前一般不用逗号。 ( 1 ) when, as, while (从属连词) when 即可引导持续性动作,又可引导短暂性动作。它可以表示主句的动作和从句的动作同时发生,或从句的动作发生在主句动作之前。如: When I was a boy, I used to go to the seashore on Sundays. (同时) When the lesson was over, we began our writing.(从句动作在前)1 、时间状语从句:引导时间状语从句的从属连词有: when, while, as, whenever, before, after, since, till, until, as soon as, once,the moment, immediately, no sooner…than, hardly…when, by the time, every time, last time… 等引导。 as 引导持续性动作,侧重主句和从句的动作同时发生。 He hurried home, looking behind as he went. I saw your sister as she was getting on the bus yesterday. He sang as he walked.While :指的是“在某一时间里”,“在… 期间”,从句里的动作必须是持续性的,它也强调主句和从句动作的同时发生,往往侧重主句和从句动作的对比。如: While he was in London, he studied music. While we were watching TV, he was writing a composition. 当 when, as, while 表示“在…一段时间里”,主从句的动作同时发生时,可以换用。如: While (When 或 As) we were discussing, Mr. Smith came in.*when 可表示“如果”。如:Don’t be afraid of asking for help_____ it is needed. (’03 全国)A. Unless B. since C. although D. when*while 可表示“虽然,尽管”。如:1)____ modeling business is by no means easy to get into, the good model will always be in demand.(’04 浙江)A. While B. Since C. As D. If 2)_____ I accept that he is not perfect, I do actually like the person.(’04 江苏)A. While B. Since C. Before D. UnlessWhen 和 while (并列连词), while 表示对照的意思。 Whe...