并且，由于它们是在地下形成的，而不是由地表水流形成，所以并不是所有的通道都有通向外部世界的开口。

And, since they were created underground and not from flowing surface water, not all these passageways have an opening to the outside world.

youdao

由高水位向低水位流动的水流形成这一盆地向另一盆地的出流和入流。

Flow from the high water level to the lower constitutes the inflow or outflow from one basin to another.

youdao