We were going to have a clicker slide on how many bounced back but it looks like we're having a little technical difficulty with that.

发生背散射，球被弹回来了的,同学请你们站起来,让我算算。

麻省理工公开课 - 化学原理课程节选

So let's do a quick clicker question, and you tell me how many valence electrons does fluorine have? Remember, valence electrons are different from core, they're only the outer-most electrons in the outer-most shell.

那么让我们来做一个小选择题，请大家来告诉我,氟有多少个价电子，要记得，价电子与芯电子不同，它们是在最外壳层的最靠外面的电子。

麻省理工公开课 - 化学原理课程节选

If you guys wouldn't mind standing up I'll introduce you so you'll put some names to faces.

我来一一介绍,请大家起立,好让大家认识你们

耶鲁公开课 - 关于食物的心理学、生物学和政治学课程节选