These incidents took place during a time of intense social and political change in the United States.

VOA: special.2010.02.25

It's a time of technological innovation, tremendous technological innovation, so much technological change that half the time it frightened people.

这还是个技术革新的时代,空前的技术革新,如此多的技术涌现,以至于人们有时候是对其感到恐惧的

耶鲁公开课 - 美国内战与重建课程节选

But luckily for us, there's a classical equation of motion that will, in fact, describe how the electron and nucleus change position or change their radius as a function of time.

但幸运的是，有一个,经典方程描述了电子和核子,位置或者它们直接的距离是,如何随时间变化的。

麻省理工公开课 - 化学原理课程节选

Senator Kerry said the time had come for a change in U.S.strategy toward Pakistan, with the aim of appealing to the hearts and minds of the Pakistani people.

VOA: standard.2009.05.04

Now,that has changed, for sure; but,the centralization of the French government and the domination of Paris over the life of the nation is very difficult to change, over a long period of time.

现在,情况已经发生了改变,但是法国政府的中央集权化,以及巴黎在国民生活中的支配地位,在相当时间段内,都很难得以改变

耶鲁公开课 - 1871年后的法国课程节选

"Whether or not they blame Karzai for that personally, I think that there is a general sense among significant parts of the population that it may be time for a change.

VOA: standard.2009.08.03

"Because it's happening so quickly, they haven't had time to adapt and change, if you imagine a climate changing over hundreds of thousands of years, bears and other animals would gradually move into other habitats,but because this is going to happen over decades, it will be too fast for them to adapt and look for other food sources,"

VOA: standard.2009.12.13