Later comes stage 2, where the alpha activity dies down.

接着来到第二阶段， α 波将完全消失。

But basically, it starts when your winding down and your brain exhibits some alpha activity.

但基本上，睡眠开始于你放松身心的时候，此刻，你的大脑充满着 α 波的状态。

You eventually enter stage 1 of sleep, where your brain waves slow down and theta-band activity is introduced, with some bursts of alpha activity still occuring.

最终你会进入睡眠的第一阶段，此时你的脑波减慢并转为 θ 波，同时也仍有些 α 波的产生。