在开学的第一天，苏格拉底告诉他的学生：“今天，我们只学一件事情。那就是前后摆动你的手臂。”

On the first day of school, Socrates told his students, "Today, we'll only learn one thing. That is to swing your arm forward and backward."

youdao

你可以看到我们如何前后摆动？

So, you see how we are oscillating back and forth?

youdao

想移动的话你也可以和他前后摆动。

If you want to move you can rock back and forth with him.

youdao

So, you see how we are oscillating back and forth?

你可以看到我们如何前后摆动？

麻省理工公开课 - 固态化学导论课程节选