It was not long ( ) he was born that his mother died.为什么填before,after为什么不...

问题描述:

It was not long ( ) he was born that his mother died.为什么填before,after为什么不...
It was not long ( ) he was born that his mother died.
为什么填before,after为什么不可以?
after为什么不可以?

It was +一段时间+before " 多久就."(此句型中不用after)
It is +一段时间+since "自从.以来有(一段时间)了"