关于曼哈顿SC 6th中的subgroup modifier的问题

抓住青春的尾巴

各位大神好,
关于曼哈顿SC 6th中的subgroup modifier,书中的例句有点不懂,请教下大家:
This model explains all known subatomic particles, SOME OF WHICH WERE only recently discovered.

This model explains all known subatomic particles, SOME OF THEM only recently discovered.

This model explains all known subatomic particles, SOME  only recently discovered.

书中说这三句都是对的,但是为什么后两句不用被动语态???

抓住青春的尾巴

alzn2765 发表于 2016-2-22 16:48
因为后两句是独立主格

同意！               

alzn2765

因为后两句是独立主格