在地下，没有外界生成的白天，而只有永恒的黑暗，人工照明形成白昼，这就可以根据人的需要加以调整。

Underground, where there is no externally produced day, but only perpetual darkness, it would e artificial lighting that produces the day and this could be adjusted to suit man's convenience.

youdao

在地下，没有外界生成的白天，而只有永恒的黑暗，人工照明形成白昼，这就可以根据人的需要加以调整。

Underground, where there is no externally produced day, but only perpetual darkness, it would e artificial lighting that produces the day and this could be adjusted to suit man's convenience.

youdao