这句话不是比较级为什么要用than？谢谢

hardly/scarcely....than...
no soone.....than...都是表"一....就...."
并且在这些固定搭配中都要用完成时,这句话的意思是"她一躺下就睡着了 "

hardly had...than... 一....就...
她一躺下就睡着了

这个牵涉到倒装句的知识点：

一, 部分倒装
1. 句首状语为否定词或半否定词的句子.
这类词或短语主要有never, neither, nor, little, seldom, rarely, not only, in no way, at no time, few, not, no等, hardly/ scarcely…when, no sooner…than, 如:
Not a word did I say to him.
Never have I found him so happy.
No sooner/ hardly/scarcely had he gone to bed than/when he fell asleep.
2. only + 状语放在句首,要部分倒装.如:
Only by this means is it possible to explain it. (介词短语)
Only then did I realize the importance of math. (副词)
Only when the war was over in 1918 was he able to get happily back to work. (从句)
3. so或so引导的短语放在句首,要部分倒装.如:
I saw the film, so did she.
So loudly did he speak that even people in the next room could hear him.
4. "Not only + 分句,but also + 分句"句型中的前一分句要部分倒装.如:
Not on