一个能够起到警示作用的事件就可以被称为 “a wake-up call，警钟 ”。为的是警告一个人避免重犯同样错误或防止将来出现更大问题。

例句

The plane crash was a wake-up call for airlines never to compromise on safety.

When I failed my mock exam it was a real wake-up call. From then on I studied and revised hard.

请注意

如果你突然发现什么不好的事情已经发生了或者正在进行中，这种情况可以用“wake up to the fact”来表达，意思是觉醒、醒悟过来。

例句

You need to wake up to the fact that you are not going to pass your exams if you don't start working harder.

It took a while for my parents to wake up to the fact that their business was failing.