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

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

学院介绍：可汗学院(Khan Academy)，是由孟加拉裔美国人萨尔曼·可汗创立的一家教育性非营利组织，主旨在于利用网络影片进行免费授课，现有关于数学、历史、金融、物理、化学、生物、天文学等科目的内容，教学影片超过2000段，机构的使命是加快各年龄学生 ...