复数，some是不定代词，可以为修饰用法，也就是后面加名词的用法；可以为指代用法，就是后面不直接加名词的用法。此处是some与of连用型的指代用法，其后既然是them，说明some是指代的复数可数名词的概念，因此为复数概念。
some of them相关例句
Some of them make him know them.
其中一些让他认识他们。
Some of them are also later sold, in order to limit the number of ponies according to the rules set by Natural England.
根据“自然的英格兰”组织制定的规则，为限制小马的数量，其中一些小马后来也被出售。
Some of them carried the guns which were the tools of their trade.
他们有些人携带着喷枪，那是干他们那一行的器具。
Some of them live in places quite a long way from here.
他们中有些人住的地方离这里很远。
Some of them make no bones about their political views.
他们中的一些人坦率地表达了自己的政治观点。