精品文档---下载后可任意编辑（一）状语从句概述定义状语从句用作状语，是起副词作用的句子。位置状语从句可以放在主句之前，也可以放在主句之后，时间、条件、原因和让步状语从句放在句首时需要用逗号和主句隔开。分类根据其作用可以分为时间、地点、原因、条件、目的、让步、方式和比较等状语从句。作用它可以修饰谓语、非谓语动词、定语、状语和整个句子。（二）状语从句详解1. 时间状语从句引导词用法示例when意 为 “ 当 … 的 时候”。When 引导从句的谓语动词可以是延续性动A liar is not believed when he speaks the truth.说谎者讲真话时也没有人信精品文档---下载后可任意编辑词，也可以是瞬间动词。并且 when 有时表示“就在那时”任。When he arrives, I’ll call you.When you laugh and smile, your body relaxes. while意为“在…的时候，在…的同时”。While 引导从句的谓语动词必须是延续性的，发生时间较长，并强调主句和从句的动作同时 发 生 （ 或 者 相 对应）。While 有时还可以表示对比。While I was standing at the window, I saw several boys running along the street. While John was watching TV, his wife was cooking. as意 为 “ 一 边 … 一 边…”。As 引导的动作是The writer was angry as he was travelling on a 精品文档---下载后可任意编辑延续性的，发生时间较短，一般用于主句和从句动作同时发生；as 也可以强调一前一后。train to London because someone had invaded his “space”.He smiled as he stood up. after意为“在…之后”。表示主句动作发生在从句动作之后。主句与从句的动作时间关系与 before 引导的从句相反。With many hungry visitors waiting, don’t stay too long at your table after you have finished.If an early exit is necessary, you can leave after a scene is over. before意为“在…之前”。引导的从句不用否定形式的谓语，并且当 before 引导的从句位于主句之后，有You can’t watch TV before you finish your homework.Before it ended, the 精品文档---下载后可任意编辑时译成“就，才”。当主句用将来时，从句总是用现在时；假如 before 引导的从句谓语用的是过去时，则主句动词多用过去完成时，这样以便体...
