Because it's dangerous
危险───DANGER;这样───such
He looks about him, sensing danger.───他环顾四周，觉察到了危险。
appeared no imminent danger.───眼前似乎没有危险。
The red triangle denotes danger.───红色三角形表示危险。
The Ministry of Defence said the vessel was not carrying nuclear weapons, and there was no danger to the public.───国防大臣表示，这艘潜艇没有搭载核武器，不会对公众造成危险。
The rate of premiums is determined on the basis of the level of industrial injury risks and that of occupational danger in different trades.───根据不同行业的工伤事故风险和职业危害程度确定不同的行业费率；
There is no doubt that global warming is a clear and present danger, and geoengineering may be part of the solution to that problem.───毫无疑问，全球变暖是一个明确而现实的危险，地质工程方法也很有可能是解决问题的一把钥匙。
All is not lost that is in danger.
Rewards allure men to brave danger.
Danger itself is the best remedy for danger.
Power invariably means both responsibility and danger.
The sheep dog protects the sheep from danger.