Housing up to 300 mole rats, these colonies feature complex underground tunnel systems, nest chambers, and community bathrooms.

一个巢穴居住着最多 300 只裸鼹鼠，这些群落以地下管道系统为显著特征，还有像大厅一样的巢穴以及公共厕所。

So a new tunnel system has been developed.

因此，开发了一种新的隧道系统。

And then there is the fighting that took place underground, with the vast intricate tunnel system that ISIS had dug out.

然后是在地下发生的战斗，ISIS 挖出了庞大而复杂的隧道系统。