有一读者问：as soon as 与 no sooner...than 都意谓“一……就……”，但在用法上有没有区别呢？
请先看下面两组句子：
(1)I'll tell him as soon as I see him.
(2)As soon as the weavers heard the Emperor coming, they pretended to work harder than ever.
(3)He had no sooner heard it than he started back home.
(4)No sooner had he arrived home than he was asked to start on another journey.
从上面两组例句至少可以看出 as soon as 与 no sooner...than...有下列三点差异：
1. as soon as 从句中可用现在一般时与过去一般时，而含有 no sooner...than 的句子的主要动词则一般须用过去完成时。
2. as soon as 强调时间概念， no sooner...than 则强调次序概念，具有 immediately after （紧接着）的含义。
3. as soon as 从句的动作与主句的动作二者一般比较协调，没有什么矛盾或冲突，如例（2）; no sooner...than 则往往表示句中两个动作是不协调的，是有矛盾的，如例（4）。
