If they had had money,they would lent you 为什么用had had呢、

题目

If they had had money,they would lent you 为什么用had had呢、

答案

这个是if的虚拟语气用法.情况分为几种：
（1）对将来的情况进行虚拟,那么主句用would+动词原形,if从句用完成时.例句：
if they have had money,they would lend you.
(2)对过去的事情进行虚拟,主句用would +过去式,if从句用过去完成时.
你所说的句子就是第二种情况,所以前面用过去完成时had had.
希望帮到楼主