Question

请高手解释一下这句话的语法，为什么要用as should be?

As should be evident by now, the number and diversity of personality theories are indeed remarkable.

Answer 1

as it should be 应该如此，本来就应该是这样。

should be是虚拟语气，表示猜测、主观愿望，也可以理解为委婉语气。

加上这里又做了as引导的条件状语，所以省略了形式主语it，it代表的是整个后半句的内容。