It's becoming more and more of a problem worldwild英语课本里的一句话,请问其中become of是什么用法不加of行不行呢?是不是因为有more才必须加of?

问题描述:

It's becoming more and more of a problem worldwild
英语课本里的一句话,请问其中become of是什么用法
不加of行不行呢?是不是因为有more才必须加of?