Stars are only visible when the sky is dark.

只有在天空不亮时才看得见星星。

youdao

The sky is dark and the wind is cold and weary.

日落天已黑，寒风刺骨知疲惫。

youdao

Sky is dark, I'm reluctant to go out of the zoo.

天要黑了，我恋恋不舍的离开了动物园。

youdao

The Evening Star is the, roughly speaking, first heavenly body that's visible in the sky as it gets dark, at least at certain times of the year.

粗略说来,昏星就是,天黑时第一个能看见的天体,至少在一年的某个时间段是这样

耶鲁公开课 - 死亡课程节选

The other half of the sky is 97% dark.

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The Dark Sky app is for weather watchers craving instant information.

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In scenes where we stare out at what I presume to be the back side of Anor Londo (a portion of the city we see but never visit in Dark Souls) the sky is the same color as the perpetual sunset over Anor Londo in the first game.

FORBES: Will 'Dark Souls 2' Be A Prequel Or A Sequel?