No sooner... than...，"一...就..."， 引导时间状语从句。主句用过去完成时，that后面的从句用一般过去时。
即:主语+had no sooner done+than 主语 did
I had no sooner raced home， than it began to rain.
No sooner放句首表示强调，主句要倒装。
No sooner had I reached home， than it began to rain.
与这个短语类似的，还有...
We had hardly got there when it began to rain.
Hardly had we got there when it began to rain.
