as soon as,
hardly…when…
no sooner…than…
这三个短语都有“一……就”、“刚刚……就”的意思，它们的意思非常相近，因此有时可以互换。例如：
“我刚到公共汽车站，汽车就开了。”一句，就可以有如下几句译法：
As soon as I got to the bus stop, the bus started.
Hardly had I got to the bus stop when the bus started.
No sooner had I got to the bus stop than the bus started.
但他们之间也有一些差异，例如，如果从两件事情的间隔时间来说，as soon as 较长，no sooner...than 居中，hardly...when 间隔时间最短。其它的一些区别见下面，请大家在运用的时候要留意。
1、as soon as
它的意思相当于“A事情发生以后，就做B这件事”。
这个短语用的比较常用，口语和书面语都可以。它的特点是，在句子中的位置比较灵
活，而且可以用于各种时态。例如：
I’ll write you as soon as I get there.
我一到那儿就给你来信。（一般现在时）
As soon as I went in, Katherine cried out with pleasure.
我一进门，Katherine 就高兴的叫起来。（一般过去时）
I’ll return the book as soon as I have read it.
我一读完就把书还回去。（现在完成时）
Andrew left as soon as he had drunk his coffee.
Andrew一喝完咖啡就走了。（过去完成时）
2、no sooner…than
它的意思相当于“刚做完A这件事，就做B这件事”。例如：
He had no sooner returned than he bought a house.
他一回来就买了一套房子。
如果no sooner 位于句首，主句要用倒装结构。例如：
No sooner had he arrived than he went away again.
他刚到就又走了。
No sooner had the game started than it began to rain heavily.
运动会刚开始，天就下起了大雨。
有一点要注意，no sooner…than 一般用来描述做过的事情，它不能用于表示将来的事。
3、hardly…when...
它的意思是“几乎未来得及做完A这件事，紧接着就开始B这件事。”
使用这个短语时，一般用于过去完成时；并且when有时可改用before。例如：
He had hardly finished the article when the light went out.
他刚写完文，灯就熄了。
He had hardly had time to settle down when he sold the house.
他还未安顿下来，就卖掉了那所房子。
另外，如果把hardly放于句首，主句要用倒装结构即谓语动词要提前。如：
Hardly had I finished eating when he came in.
我刚吃完他就进来了。
Hardly had she gone out when a student came to visit her.
她还没走出家门，就有一个学生来看望她。
as soon as用法
英语动词的时间大致可分为三段：过去时、现在时、将来时。假设有两件事A和B，就会出现三种情况：
A 过去时 as soon as B 过去时
A 现在时 as soon as B 现在时
A 将来时 as soon as B 将来时
在每一个大的时间段内，A 和 B 的时态要统一。比如 A 过去时，B 肯定在过去时内。其它也是如此。至于在每个大时间段内，再根据A 和 B两件事的具体情况，具体对待。比如：A 和B都时过去时，A 和 B 是同时发生，还是先后发生，不是即将发生，再分别选用完成时、进行时、将来时。例如：
A 过去时 B 过去时：
I arranged the flowers in the vase as soon as I came back home.
一回到家里，我就把花在花瓶里插好。
A 过去进行时 B 过去完成时(虚拟)
He was shaking with fright as if he had seen a ghost.
他吓得直哆嗦，就好像看见了鬼一样。
A 将来时 B 将来时(可用一般现在时表达)
They will post me the tickets/post the tickets to me as soon as they receive my cheque.
他们收到我的支票后就立刻把票寄给我.
as soon as连接的时间状语从句中，指未发生的动作，规律是：主句一般将来时，从句用一般现在时代替一般将来时
如：I will tell him the news as soon as he comes back。
指紧接着发生的两个短动作，主从句都用一般过去时
如 He took out his English books as soon as he sat down
就这两种情况 ，熟记就行。
在宾语从句中，当主句为与过去时的时候，从句必须用与主句相对应的时态，所以为了与主句动词said呼应，时间状语从句中的will look up应该对应为过去将来时态would look up，finds对应为found
