表示一……就的词组有很多。常用的有：

as soon as

the moment/minute/second/instant

immediately,

instantly

hardly...when...

no sooner...when...

最后多用于叙述过去的事情。

他一回到家，就马上上网：He surfted the Internet as soon as/ the moment he arrived home.

2. How long do you need? Is five minutes enough? / How much do you need? Is five dollars enough? (时间和金钱等作主语，看成一个整体，谓语动词用第三人称单数形式）

3. I only need five minutes. Five dollars is enough.