in spite of all that has been said,这里的all和that怎样用

题目

in spite of all that has been said,这里的all和that怎样用
是什么用法 all that=what吗，为什么不用what

答案

all 代指“that has been said"

用what 替代也可以啊.但是all that暗含一种强调：“所有”说过的.