经济不景气导致了成千上万小企业的倒闭。

A poor economy has caused the ___collapse of thousands of small businesses.

两国之间的谈判濒临崩溃。

Negotiations between the two countries are on the brink of ___collapse.

在教书十年后，他精神崩溃了。

He suffered a mental ___collapse after ten years' teaching.