表示"一…就…"的結構
hardly/scarcelywhen/before, no soonerthan 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，句子必須用倒裝結構：
Hardly / Scarcely had I got home when it began to rain.
No sooner had I got home than it began to rain.
