It's the problem that sometimes people knock over an oil lamp in their home and they burn their own house down.

有时候会出现这种问题,一个人把自己家里的油灯弄翻了,然后把自己的房子点着了

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So, if you use a black lamp or something and you excite something up to a higher energy level and then it relaxes back down to its lower energy state, it's going to emit a new wavelength of light, which is going to be visible to you.

如果你用一个紫外灯或别的,东西把某种分子激发到,更高的能级，然后它会掉回,到低能级，它就会释放,一个新的波长的光,这个光是可见的。

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