请问一下一个词组都可以翻译成一...就...，请问在用法上有什么区别吗

几乎没有什么区别!只在语气上有所区别：
no sooner...than的语气最强，hardly次之，scarcely再次之,barely语气最弱。

hardly...when...表示“一……就”
scancely/hardly...when/before和no sooner...than(都是一...就的意思)句型要注意倒装
如"He has no sooner understood than he reads"变成
No sooner has he understood than he reads.

这些词组都可以互换,都要用倒装,如:
Hardly had he left home when it began to snow.他刚出门,雪就开始下了.
as soon as 一...就... 这个词组不能用倒装,如:
As soon as he left home,it began to snow.