Some critics have questioned why the president is traveling at a time when so many pressing matters are before him not just Afghanistan, but also the U.S.economy and his ongoing campaign for health-care reform.

VOA: standard.2009.11.12

But Hobbes lived at a time when the modern system of European states even as we understand them today, was just beginning to emerge.

霍布斯生活在一个时代,这个时代中，现代欧洲国家,就像我们今天理解的这样，已经快要出现了。

耶鲁公开课 - 政治哲学导论课程节选

but it's just like a time when they really took the care to look at how to construct things.

但它代表了一个时期，那时他们真正关注搞建筑的方法。

我喜欢的建筑物 - SpeakingMax英语口语达人

I just go down the list selecting the smallest person at a time and then I repeat, repeat, repeat but when we actually did out the math or kind of reason through it, the running time, the asymptotic running time of bub-- of Selection Sort was also what?

只需要遍历列表，每次找出最小的元素,然后重复上述步骤，但从数学角度看,选择排序的时间复杂度,又是多少呢？

哈佛公开课 - 计算机科学课程节选