Now, I've just talked a lot about waste clearance, but I haven't been very specific about the kinds of waste that the brain needs to be clearing during sleep in order to stay healthy.
到现在，我们已经说了很多关于废物清理的事 但是我还没有具体介绍 废物的种类—— 那些为了保持我们健康， 大脑必须要清理的废物——的种类。