Modern life makes us tired, right? But research from societies in Africa and South America suggests people in the ancient world slept only 6.5 hours a night.

但你可能会发现，很多喜欢吸烟的人，身上都会有很重很难闻的烟味，有些亲戚家的室内也有一股呛人烟味。 吸烟者留下的烟草残留物，往往会与空气中其他常见的污染物继续发生反应，逐步形成 11 种高度致癌物。

Modern life makes us tired, right? But research from societies in Africa and South America suggests people in the ancient ...