The volume seems to alternate between very loud and very soft.

音量似乎在很响和很轻之间交替。

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Throughout the night, people alternate between passive and active sleep.

整个夜晚，人们被动和主动之间轮流睡觉。

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Throughout the night, people alternate between passive and active sleep.

整个夜晚，人们被动和主动之间轮流睡觉。

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