There was another bag of brown dirty skin at the back of it.这句里的bag作何解释?

问题描述:

There was another bag of brown dirty skin at the back of it.这句里的bag作何解释?
There was another bag of brown dirty skin at the back of it
书上的中文解释是:脑后还耷拉着一块褐色的,肮脏的头皮.
这句中的bag怎么讲?

一块儿.bag有大量的意思.