Last week,U.S.President Barack Obama said there was "an almost reflexive anti-Americanism", which was stopping some countries from stepping up to the plate.

VOA: standard.2009.09.28

We have a zinc plate up here, and we're going to -- in a minute I'll describe how we can probe if electrons are coming off of it.

我们有一块向上的锌板，我们将在一分钟内描述,我们是怎样探测出,是否有电子从上面射出的。

麻省理工公开课 - 化学原理课程节选