状语从句按其意义和作用可分为:a)时间状语从句b)地点状语从句c)原因状语从句d)目的状语从句e)结果状语从句f)条件状语从句g)方式状语从句h)比较状语从句i)让步状语从句2.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, hardlywhen, no soonerthan等引导。如：When he was still a young man, he was forced to leave his homeland for political reasons.注意：a)when, as, whilei.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
