when (it) comes to saving energy,a big changes st
问题描述：
when (it) comes to saving energy,a big changes st
when it comes to saving energy,a big changes start with small steps,like turning off the lights.为什么括号里用it不用that或别的?
答
when it comes to xxxxx 这是个句型,平时可以记住也这样用；它是用it来指代任何xxx
表示意思为 当谈到xxx,说到xxx
请楼主斟酌,