Question

The children , all of them had played the whole d

The children , all of them had played the whole day long, were worn out.
此题为语法填空题。请详细分析一下，为什么将them改成whom,请说明一下理由，十分感谢。
谢谢。

Answer 1

whom 指代 the children, 如果用them，中间不是个介词短语而是个句子

Answer 2

这个句子的中间部分是非限制性定语从句，先行词是the children, 而of是介词，所以关系代词用whom。

Answer 3

all后面全是定语从句，不完整句子，不能出现主谓宾的完整结构，用whom代替。

Answer 4

The children , all of whom had played the whole day long, were worn out.

them改成whom 

1. 去掉中间部分，all of whom had played the whole day long，剩下部分是完整的句子。

2. all of whom had played the whole day long，是定语，修饰主语the children.

  3. all of them had played the whole day long 这是个完整的句子。 如果写them，这个句子有两个主谓宾。

Answer 5

很简单，whom特指前面的the children，这样一来就可以省略逗号