"I honestly believe that you don't really understand what freedom is until you've had that freedom taken away."

VOA: standard.2010.03.25

for exam 2, you still need to know and understand everything you learned in exam 1, but you can put off learning it completely until we get through, at least, next Wednesday before we start maybe spending time on these concepts outside of class.

为了掌握第二次考试的内容，你仍然需要知道和理解,在第一次考试前所学的全部知识，但是你可以先放一放，等到我们进行到，至少在下周三我们可能开始不在课堂上,讲这些内容之前。

麻省理工公开课 - 化学原理课程节选