His stomach seemed a bottomless pit.

他的胃似乎是个无底洞。

youdao

A gold mine is not a bottomless pit, the gold runs out.

一个金矿不是无限的，黄金采光了。

《柯林斯英汉双解大词典》

There isn't a bottomless pit of money for public spending.

公共开支并非用之不尽。

《牛津词典》