湖南 李茂盛
　　
　　状语从句按其意义可分为时间、地点、条件、原因、目的、结果、让步、方式、比较等九种。
　　
　　复习时我们要正确把握各种连词引导的从句类型，牢记各个连词的不同用法和词义。
　　
　　一、时间状语从句
　　
　　1. 能引导时间状语从句的引导词有三种：（ 1 ）从属连词： when, while, as, after, before, since, till, until, as soon as, hardly / scarcely … when, no sooner … than 等。
　　
　　（ 2 ）名词短语： the moment, the minute, the instant, each time, the first time, the last time, next time 等。其中 the moment, the minute, the instant 相当于 as soon as, 意为“一……就”。（ 3 ）副词 immediately ， directly ， instantly ，意为“一……就”。
　　
　　2. 时间状语从句中表示将来发生的动作时不能用将来时，一般现在时要用一般现在时取代，过去将来时要用一般过去时取代，将来完成时要用现在完成时取代，将来完成进行时要用现在完成进行时取代。例如：
　　
　　Take the medicine before you go to bed.
　　
　　Don't get off the bus until it has stopped.
　　
　　When he has been teaching here for five years by next spring, he will get a rise.
　　
　　3. 注意 when / while / as 的区别：（ 1 ） when 引导的时间状语从句中的动词可以是延续性和非延续性动词；此外， when 还有“这时”和“在……之后”的意思。 while 从句中的动词应为延续性动词；此外， while 还可表示对比。 as 可表示“一边……一边；随着”。（ 2 ）若 when 引导的从句是系表结构，且从句和主句的主语一致时，则可用 as 引导的省略句来替代。例如：
　　
　　As （ =When he was ） a child, he liked to play his violin.
　　
　　4. 注意 as soon as / no sooner … than / hardly … when 的区别： as soon as 引导时间状语从句时，表示主句和从句的动作紧接着发生，可与 the moment / the minute / the instant / immediately / directly / instantly 互换。 no sooner … than 与 hardly … when 用法一样， no sooner 和 hardly 之后一般要用过去完成时， than 和 when 之后用过去时；若 no sooner, hardly 放在句首时，则主谓要倒装。例如：
　　
　　As soon as /The moment / The minute / The instant / Directly / Immediately /Instantly he comes, please let me know.
　　
　　He had hardly finished his homework when he went to bed. = He had no sooner finished his homework than he went to bed. = No sooner had he finished his homework than he went to bed. = Hardly had he finished his homework when he went to bed.
　　
　　摘自 考试报