In 2007,expenditures on health care totaled about one-sixth of the entire U.S.economy, and even top congressional leaders acknowledge that attempting to rein in health-care costs while at the same time expanding health-insurance coverage is a daunting task.

VOA: standard.2009.07.31

That's why your operating systems and your personal computers often crash for no apparent reason. Just because two things happen to, once in a while, occur at the same time.

这就是为什么你的电脑或者操作系统,经常会毫无预兆的崩溃了,这是因为两件事情正好同时发生了，通常还有人工输入。

麻省理工公开课 - 计算机科学及编程导论课程节选

We normally think of teaching as a synchronic process, you and I are in the same place and in the same time while we are learning, when in fact at least right now we are not.

我们通常设想教学是限于一时的过程，你我在同一地点,同一时间学习，但事实上至少现在就不是这样。

麻省理工公开课 - 媒体、教育、市场课程节选

Mr.Ahmadinejad's assault against opposition leaders comes at a time when he is being criticized by his own supporters for using poor judgment in trying to form a new government, and while Supreme Leader Ayatollah Ali Khamenei has softened criticism of the opposition.

VOA: standard.2009.08.28

And you can see it wrapping its way down, cutting in half at each time until it gets there, but it takes a while to find. All right.

但是这也花了一点时间来搜索，好，让我们看看100万，或者1000万是不是在数组里。

麻省理工公开课 - 计算机科学及编程导论课程节选

Remember, this is a time, as we'll see in a while, where the czar was on the road a lot, and distances in the Russian empire are enormous.

要记得一点,我们后面还会讲到,因为彼得大帝经常外出,而当时的俄帝国幅员辽阔

耶鲁公开课 - 欧洲文明课程节选