可汉学院（Khan Academy） -超过1200个视频教程，内容涵盖自基础算术、代数至微分方程、物理学、化学、生物学和金融学。

Over 1200 videos lessons covering everything from basic arithmetic and algebra to differential equations, physics, chemistry, biology and finance.

youdao

可汉学院（Khan Academy） -超过1200个视频教程，内容涵盖自基础算术、代数至微分方程、物理学、化学、生物学和金融学。

Over 1200 videos lessons covering everything from basic arithmetic and algebra to differential equations, physics, chemistry, biology and finance.

youdao