That's a known danger sign, like drinking alone.

这是一种明显的危险信号，有点像一个人喝闷酒。

youdao

Subconsciously I had known that I would not be in personal danger.

下意识地，我已经知道了我将不会有人身危险。

《柯林斯英汉双解大词典》

As is known to all, the panda is in danger of becoming extinct.

众所周知，熊猫濒临灭绝。

youdao

He says intelligence sources and methods will become known,and Afghans who have helped American forces may now be in danger.

VOA: special.2010.07.31

If a teenager enters any known danger zones, their phone will make a sound alert and vibrate to let them know they are in an unsafe area.

BBC: Will the next Zuckerberg be female?

This may be the best-known danger in derivatives dealing: everyone in the markets knows that if shares stop trading or the share prices become much more volatile than expected, an option's market value will differ from the model's valuation.

ECONOMIST: Blind faith

Current U.S. strategy calls for riding out a nuclear attack if necessary, which reduces the danger of having to launch on warning before all the facts are known but increases the danger of being caught on the ground in a surprise attack.

FORBES: Nuclear Weapons: How Few Is Too Few?