The book is kept by the Library of Congress and has never been used at another swearing-in.

VOA: special.2009.01.19

There are still some active smallpox virus specimens kept in the world, and there are two sources of small--two places where smallpox is stored now.

世界上仍有地方保存着,一些具有活性的天花病毒样本,有两个地方还储存着天花病毒样本

耶鲁公开课 - 生物医学工程探索课程节选

One is in the U.S.at the Centers for Disease Control, where there is a sample of variola, which is kept, you know, frozen on ice in a heavily guarded facility.

一个在美国的疾病控制中心,那有一支天花病毒的样本,冰冻后置于重重保护之下

耶鲁公开课 - 生物医学工程探索课程节选

Food stored in the smaller pot is kept from spoiling through a simple evaporation process.

VOA: special.2009.02.09

So that should mean that the energy that's transferred to the electron should be greater, but that's not what you saw at all, and what you saw is that if you kept the frequency constant there was absolutely no change in the kinetic energy of the electrons, no matter how high up you had the intensity of the light go.

所以这意味着转移到电子,上的能量也越大，但这并不是，我们观测到的现象,我们所看到的是,如果固定光的频率不变,不管光强如何变化,电子的动能没有任何变化。

麻省理工公开课 - 化学原理课程节选

An ace in the hole is an argument, plan or thing kept hidden until needed.

VOA: special.2009.11.22

I don't think they were having very good success, but they did notice something interesting which is that the rat kept returning to the corner of the cage in which it was stimulated the day before So Olds got an interesting idea, he said, what if we let the rats stimulate in its own brain, what would happen.

他们的试验并不是非常成功，但他们确实是注意到了一些有趣的事情,老鼠总是会回到,昨天接受刺激的那个箱子的角落,因此奥兹产生了一个有趣的想法，他想，如果我们让老鼠在自己的脑中对自己进行刺激会，发生什么事情。

斯坦福公开课 - 7个颠覆你思想的演讲课程节选

You'll be kept in prison for a long time.'" But in reality,there is help.

VOA: special.2010.06.14

Experts say the risk is low, in part because weather systems have kept the oil away.

VOA: standard.2010.07.05