hardly/scarcely…when/before, no sooner…than 和as soon as都可以表示"一…就…"的意思,例:
I had hardly / scarcely got home when it began to rain. I had no sooner got home than it began to rain. As soon as I got home, it began to rain.
注意:如果hardly, scarcely 或no sooner置于句首,句子必须用倒装结构: Hardly / Scarcely had I got home when it began to rain. No sooner had I got home than it began to rain.