在睡眠的各个阶段，呼吸道中产生了一些变化。

During all phases of sleep, several changes in the air passages have been observed.

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大脑半球轮流进入以慢脑波为特征的睡眠阶段。

The brain hemispheres take turns sinking into the sleep stage characterized by slow brain waves.

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在不同的睡眠阶段，我们的学习方式可能会有所不同。

We may learn differently during different sleep stages.

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You start off and you go down, down, down, and then you come up, then you get your first REM cycle, again, again, again, again, again, and then you wake up.

从第一阶段开始，到下面的阶段，然后又往上，这时就出现REM睡眠，然后再一次次地循环，直到你睡醒。

耶鲁公开课 - 心理学导论课程节选