求助：过去将来完成时

observer

那位大虾能给我指点一下过去将来完成时即would have done 的用法。

对应的例句如下：

For many people, household labor remains demanding even if they can afford household appliances they grandparents would have found miraculous.

为什么不直接用would find呢？

observer

自己顶！！！