what引导表语从句， that和who怎么区分？

Question

如题所述

Answer 1

1、He is no longer the man that he was fifteen years ago.

〔解析〕that 和 who(m) 都可以指代人。who(m) 指代具体的人，that 指代抽象或物化的人。
2、He's what is known as a “bellyacher”——he's always complaining about something

〔解析〕what is known as a “bellyacher" 是表语从句，what 属于关系代词型连词，相当于 “先行词＋关系代词”，即 He's such a person that/who is known as a “bellyacher" (他是大家都知道的那种大声抱怨的人)