saying

我听不清他们在说什么。

I can't hear what they are ___saying.

正如俗话所说，“欢乐时光总觉短。”

As the ___saying goes, "Time flies when you are having fun."

但正如谚语所说，‘快乐时光飞逝’。

But as the ___saying goes "Time flies when you are having fun".