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。

youdao

With that big of an opening, however, you might get too much light in the camera and your picture could be overexposed, almost a whiteout.

在这么大的开启状态之下，你也有可能将太多的光放进了相机里，以至于照片过曝，甚至几乎变白。

youdao

Opening up the door, in the light of the corridor, I found stunningly that fahter was standing in front of me!

打开寝室的门，借着楼道里暗暗的灯光，我不禁一惊，竟是父亲！

youdao

I sat up. I could see light from an opening.

VOA: special.2010.07.31

And every night, late at night, I turned the lock of his door and opened it C oh,so gently! And then, when I had made an opening big enough for my head, I put in a dark lantern, all closed that no light shone out, and then I stuck in my head.

VOA: special.2009.05.16

An economic impact assessment commissioned by the Stonehaven Town Partnership (STP) has said re-opening the road to light vehicles could be worth millions of pounds each year.

BBC: Bervie Braes

Standing at a nonthreatening four feet and weighing about 95 pounds, the C-3PO wanna-be can move around the house, flipping light switches, opening doors and doing simple tasks at tables and benches.

FORBES: Ten O'Clock Tech: Robots Dawning

About 80ft high, I'd guess, it is beautiful rather than vast - a rushing stream that catches the light from an opening in the forest canopy and plunges into a pool where there were two people bathing, and from which, surprisingly, they produced a large basket of freshwater crabs.

BBC: Following Graham Greene to Liberia's sacred waterfall