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。

首先你要明白the children是主语，had played the whole day long 是定语，用来修饰the children的

如果你在这个句子中用them，那么the children和all of them 就都变成了主语。因为你看啊，这两个句子都是通的：
The children were worn out.
All of them were worn out.
你用哪一个当作主语，另一个都得哭，是不是？

如果你在这个句子中使用whom, whom 在这里代指the children而且whom不能做主语，你看：
all of whom were worn out 不是一个句子。在这里用whom而不是用who是因为whom做宾格用在介词后面

定语从句

中间没有but这类的连接词，要用定语从句

你好！ 定语从句，后面的all of……day long都是用来形容the children，用whom是表示谁的意思，用them就没有形成从句的意思了。 如果用them就应该这么说：the children were worn out，all of them had…… 仅代表个人观点，不喜勿喷，谢谢。