The Morning Star is that heavenly body which is the last heavenly body that's still visible as dawn comes in and it begins to get light.

晨星就是,这样一个天体,它是黎明来临,天快亮时,还能看到的,最后一颗星星

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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

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