The cause of the opening and closing is probably the difference in light.

开启和关闭的原因可能是光线的不同。

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Although we talked about Vitamin D and sunlight, it can make a huge difference in how you feel if you go to a tanning salon to get some light on your skin.

尽管我们已谈到维生素D和阳光，但是如果你刻意去参加日晒沙龙来摄取阳光到皮肤的话，它会让你感觉到巨大的差别。

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Then she was able to capture the sharp difference between light and dark.

VOA: special.2009.05.10

And what we predict as an energy difference between two levels, we know should correspond to the energy of light that's either emitted, if we're giving off a photon, or that's absorbed if we're going to take on a photon and jump from a lower to a higher energy level.

我们预测，两个能级之间的能量差，我们知道，它要么和发出的光有关,如果它发出光子的话，要么它吸收光子,从低能级跃迁到，更高能级上去。

麻省理工公开课 - 化学原理课程节选

And Einstein credited de Broglie, which is a fair statement of lifting a corner of the great veil, because really there was this fundamental misunderstanding about what the difference was between matter and light, and the reality is that they can both be like-particles and they can both show characteristics of waves.

并且爱因斯坦相信德布罗意，他做了一个公正的论述,揭开了一个伟大面纱的一角，因为关于物质和光,以前确实存在着,根本性的误解，真实情况是它们同时,具有粒子和波的特性。

麻省理工公开课 - 化学原理课程节选

The only difference is the light.

WSJ: Lighting Designer Al Gurdon: The Light Master of Super Bowl Halftime

All of these questions can be explored in the interactive calculator CNN created to help shed light on the difference in legal protections among the 50 states.

CNN: America is at a crossroads on gay rights

The key difference is that instead of focusing the light on a strip of photochemical film as in traditional cameras, digital cameras use an image sensor, called a charge coupled device (CCD), to capture the image.

FORBES: Technology briefing