I once landed on my face. I soon learned that it took much less effort for me to move on Mars than it did on Earth.

VOA: special.2010.07.10

I once went to visit the summer palace that he created and that Nicholas II loved so much there.

我曾到过他修建的夏宫看过,据说尼古拉二世特别喜欢那个地方

耶鲁公开课 - 欧洲文明课程节选

This novel--as you will soon see, Onnie Jay Holy once you get to the parts where Onnie Jay Holy begins to preach-- this novel is very much a critique of sentimentality.

这本书--你很快会看到，当你一读到,开始传道的部分-,这本书就几乎成一部对多愁善感的评论。

耶鲁公开课 - 1945年后的美国小说课程节选

Once, Paul rolled over so much in his sleep that he caused an earthquake.

VOA: special.2009.01.24

Pretty much I think about it only once a year, when I'm giving this very lecture.

最多是一年想一次，当我要上这节课时。

耶鲁公开课 - 死亡课程节选

and Robert Downey Jr.is,once again, both "Iron Man" and Tony Stark in the sequel that Downey hopes audiences will like as much as they did the original.

VOA: standard.2010.05.19

We don't always want to go and solve the Schrodinger equation, and in fact, once we start talking about molecules, I can imagine none of you, as much as you love math or physics, want to be trying to solve this Schrodinger equation in that case either. So, what Lewis structures allow us to do is over 90% of the time be correct in terms of figuring out what the electron configuration is.

我们并不想每次都去解薛定谔方程，而且实际上，一旦我们开始讨论分子，我可以想象,你们中没有一个人，不管你有多么热爱数学或物理，会想去解这种情况下的薛定谔方程,总之，路易斯结构能让我们,有超过，90%，的概率判断出正确的,电子排布。

麻省理工公开课 - 化学原理课程节选

The dominoes have been set up to run for one and a half kilometers in an area where the Wall once stood, and late Monday they will be toppled much like the Wall was two decades ago.

VOA: standard.2009.11.09