So, I've never heard the click-click-click-click-click, and we might bring a Geiger counter in here some time later in the semester so we can check all of you out, and hopefully we won't hear any when we do that either.

但我知道如果,你听到哒哒哒的声音，就表明你有麻烦了，我从来没听到过哒哒哒的声音,也许以后我可以带一个,来课堂上检测你们每一个人，希望我们不会听到哒哒哒的声音。

麻省理工公开课 - 化学原理课程节选