If something bad happens, please tell me.

如果有什么坏事发生，请告诉我。

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The patrol can detect if something is going down or is about to go down.

巡逻队能发现是否有情况正在发生或即将发生。

《柯林斯英汉双解大词典》

We don't have any openings now, but we'll call you if something comes up.

眼下我们没有空缺的职位。如果有了，我们会给你打电话的。

《柯林斯英汉双解大词典》

If something is new and improved, we say it is the best thing since sliced bread.

VOA: special.2011.02.20

So, if something cycles through five wavelengths in a single second, we would just say that the frequency of that wave is five per second.

如果一个东西在一秒,内经历了五个波长，我们就说这个波的,频率是每秒5次。

麻省理工公开课 - 化学原理课程节选

Or, if something goes wrong, trying to think of, you know, what can be learned out of it.

或者是，什么东西出错了，我就试着，想一想可以从中学到些什么。

幸福的定义 - SpeakingMax英语口语达人

Just play by the rules, so that if something wrong happens, here's who's responsible.

WSJ: For Graduation, a Gift of a 529

Problems are rare and if something ever came up Amy got it resolved with customer service.

FORBES: How Amy Promotes This Old House

"If something feels good to you, there isn't anybody who can persuade you differently, " Wyatt said.

CNN: Coming out late in life complex but not unusual