And as a reminder, hopefully I don't need to remind any of you, but exam 1 is on Wednesday, so rather than our clicker question being on something from last class, which is exam 2 material, let's just make sure everyone remembers some small topic from exam 1 material, which is the idea of angular nodes.

而作为一个提醒--我希望大家都不需要提醒，但是这周三就要进行第一次考试了，因此我们的这个选择题,不是关于上节课内容的，那是第二次考试的内容，这里只是想确认大家都记得,第一次考试所要求的一些小问题，也就是关于角向节点的概念。

麻省理工公开课 - 化学原理课程节选