英语 必修二 语法答:1. 由when, whenever, as , while, after, before, until, till, since, once, as soon as, 等引导的时间状语从句。1> When the bell rang, the guard was waiting in his seat. 2> While ants grow they change their forms three times. 3> Three months went by before Aqiao knew it. 2. 由...