For example, you can imagine that having a sudden and unexpected failure in your HVAC can run you several thousand dollars.

比如，你可以想象，你的空调系统突然出现问题，这可能就要花掉你几千块钱。

youdao

Today, I was showing my Mom how to use the Internet on her phone. As there was bad reception, it said "Unexpected Failure."

今天我教老妈用手机上网，信号不太好，提示有意外错误。

youdao

Courage for some sudden act, maybe in the heat of battle, we all respect, but there is that still rarer courage which can sustain repeated disappointment, unexpected failure, and shattering defeat.

我们都会对在战火中爆发出的英勇壮举表示出自己的敬意。但是还有一种更难能可贵的勇气就是在屡遭失望、出乎意料的失败，粉碎性的挫败后依旧奋力前行。

youdao

First, establish if a firm is so large or so entangled within the financial system that its unexpected failure could be catastrophic.

ECONOMIST: Saving Wall Street

It begins with an unexpected, persistent failure of the economy to grow.

WSJ: Jenkins: Lost Decade, Revisited

One or two have been unexpected successes, and early predictions of failure have proved inaccurate.

BBC: Is Blair a butcher?