关于这句英语句子的结构

题目

关于这句英语句子的结构
I've discovered i posses a large number of different talents and skills that i never would have thought were within me had it not been for my being open to trying new opportunities.
had it not been for .这里的几个词在句子中是修饰哪个部分的啊?怎么这里的结构怪怪的,

答案

had it not been for .是虚拟语气省略if,助动词提前的强调倒装句.I've discovered (that) i possess a large number of different talents and skills that [i never would have thought] were within me if it had ...