知乎，让每一次点击都充满意义 —— 欢迎来到知乎，发现问题背后的世界。Major Hat dynamic eTexts are optimized for an interactive, Energetic learning working experience. Educators can adopt—and adapt—any e-book to suit the desires of their system.这篇文章每月都会更新，可以收藏，如果对您有帮助�