i went into the kitchen,i turned on the light ,it was dark.(用on going because造句)

题目

i went into the kitchen,i turned on the light ,it was dark.(用on going because造句)
on going into the kitchen,i turned on the light because it was dark.请问,on 在这里启一个什么作用,为什么用on 又为什么went变成going,on going这是一个什么形式的语法,请详解

答案

on译为"在……后立即……","在……时","在……之后"其后跟动名词或名词.例如:
On thinking about the idea, I decided against it.经仔细考虑,我决定反对这个构想.
On arriving there, we all set to work.我们一到那儿,就开始干起来.
On reaching Paris, they called at the wine shop.一到达巴黎,他们立即就到那家酒店去了