So, if something cycles through five wavelengths in a single second, we would just say that the frequency of that wave is five per second.

如果一个东西在一秒,内经历了五个波长，我们就说这个波的,频率是每秒5次。

麻省理工公开课 - 化学原理课程节选

Here is the second nitrogen, one, two, three, four, five.

这是第二个氮，一二三四五。

麻省理工公开课 - 固态化学导论课程节选