A gold mine is not a bottomless pit, the gold runs out.金矿不是取之不尽的, 金子总有采完的时候。

The problem is we don't have a bottomless pit of resources.问题是我们没有无穷无尽的资源。

He's a bottomless pit as far as food is concerned.在吃这方面, 他是个无底洞。