英语特殊疑问句中的从句？

Question

看到一个疑问句 what could he have done that would warrant such a punishment ?
想知道这个特殊疑问句里的that 后面的句子是结果状语从句吗？那that从句中 would前面为什么没有主语？是省略了吗？

Answer 1

先不以疑问句来看

what (the thing which) he could have done. It would warrant such a punishment.

it 指 前面的 整件事 能用一句话表达就不用2句

what (the thing which) could he have done that would warrant such a punishment?

that 指前面提到的事情 代指整个前面部分 that 自己就是主词

变疑问句助动词位置改变 这些基本的不多说

2. 注意虚拟语气

what (the thing which) had he done that warranted such a punishment?

what (the thing which) could he have done that would warrant such a punishment?

明明第一句可以表达 还要加上 could 和 would,

表示是于事实相反的。

句子意思是 什么事情他做了，就会受到如此惩罚？

整个意思都在虚构，没有发生过

Answer 2

warrant such a punishment ?
想知道这个特殊疑问句里的that 后面的句子是结果状语从句吗？那that从句中 would前面为什么没有主语？是省略了吗？

Answer 3

不是状语从句吧。that would...后面的东西应该是一个名词性从句，用来描述what的。这句话的意思应该是他怎么会做可能会受到惩罚的事。