Once you get a formula, you've got to always remember the terms under which the formula was derived.

使用公式时,你一定不能忘记,公式使用的前提条件

耶鲁公开课 - 基础物理课程节选

Because it's hard when you go back being part of any group. Once you are in that group, and away from other people, it's very hard to remember We've talked that -Oh, have you?

因为如果你回到原来的群体中,就会变得难了，因为你只要一呆在那个群体中，远离其他人，就很难,我们聊过这个，-是吗？

普林斯顿公开课 - 人性课程节选

In class on Monday, we did go over the geometries, and the geometries themselves are very straightforward, once you know what the Lewis structure is, but remember, you can't just always look at a molecule and automatically know the Lewis structure.

在周一的课上，我们讲过了几何形状，一旦你们知道了Lewis结构，这些几何形状是十分直接的，但记住，你不能总是仅仅看一眼,分子就知道它的Lewis结构。

麻省理工公开课 - 化学原理课程节选