为什么It feels good to be able to 与It feels good being able to.

问题描述:

为什么It feels good to be able to 与It feels good being able to.
为什么不能用being代替to be?
It feels good to be able to meet a need like that.
It feels good being able to meet a need like that.

这里是it作形式主语指代后面的动词不定式,等同于To be able to ...feels good.就是一种固定的用法,现在分词无此用法.