Question

no sooner......than用法

Answer 1

no sooner... than... "一...就..."

引导时间状语从句,主句用过去完成时,"than"后面的从句用一般过去时.(从这里可以知道,no sooner后面是主句;than后面是从句)
例:
I had no sooner reached home than it began to rain.
我一到家天就下起雨来
No sooner ...than...常放在句首,表示强调.这时主句要倒装.
例:No sooner had I reached home than it began to rain.
与这个短语类似的还有 hardly ... when
意思为:"还没...就..."
例:
We had hardly gotten there when it began to rain.
我们还没到那儿,天就下起雨了.
(主句用过去完成时,从句用一般过去时)
Hardly...when...也常放在句首
例:
Hardly had we gotten there when it began to rain.
就是这样

Answer 2

no sooner 。。。than 一.......就......（只用于过去式）
no sooner引导的从句中谓语动词用过去完成时，当no sooner移到句首时，从句部分要倒装；than后面用一般过去时。
Eg：No sooner had he entered the room than the telephone rang.
(=He had no sooner entered the room that the telephone rang.)
（他一进入房间电话铃就响了。）

希望能帮到你！！