翻译：太阳最美的时刻，就是快要落山的时候

The most beautiful moment of the sun is going downhill when the

或

The solar most beautiful time, is the time which soon sets

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The most beautiful moment of sun, when being to set imminently

The most beautiful moment of daytime is the moment that sun sets.
（白昼最美丽的时刻，就是太阳落山的那刻）

the most wonderful moment of sun is when it falling behind mountains.

the most beautiful period of the sun,is sunset

The most beautiful moment of the sun is sunset

The most beautiful moment of the sun is going down-hill time.