Question

英语问题

Many people, some of whom are not overweight, are going on diet.
为什么是用whom而不是用them？

Answer 1

some of whom are not overweight是Many people的同位语，如果是them的话，就是完整的一个句子，中间不能用逗号分隔了。

Answer 2

你说他们中的一些，怎么说？some of them是吧？这里同理，但这是定语从句，就用whom了。whom指代many people

Answer 3

some of them are not overweight.完整句子
Many people are going on diet.完整句子
逗号不能连接两个完整句子。所以把 其中一个变成定语从句。也可以加连词，Many people are going on diet，and some of them are not overweight.