bottomless pit
noun[Cusually singular]
uk/ˌbɒt.əm.ləs ˈpɪt/us/ˌbɑː.t̬əm.ləs ˈpɪt/something thatseemsto have nolimits, or asituationthat will never end
无底洞；无休止的情形
We'll bepouringmoneyinto abottomlesspitif wetrytokeepthatfactoryopen.如果继续让那个工厂运转下去，我们无异于把钱投入无底洞。