He says the global economy must change to a sustainable system now before social issues and ecological degradation become overwhelming.

VOA: standard.2010.01.23

We looked at pressure change before, actually, in discussing the third law, the fact that the entropy goes to zero as the absolute temperature goes to zero for a pure,perfect crystal.

在讨论热力学第三定律的时候，我们讨论过压强变化,即对于纯净的完美晶体,随着温度下降到绝对零度熵也变成零。

麻省理工公开课 - 热力学与动力学课程节选

That doesn't solve the problem we had before though Then I'm going to append it, and keep the last change for future use.

这样没有解决我们之前的问题,所以我要给它加上一个值，让上一次的变化能够用到未来的例子中。

麻省理工公开课 - 计算机科学及编程导论课程节选

Administration officials say the United States needs to make sure it has a credible partner in the Afghan government before any change in strategy.

VOA: standard.2009.10.21

as we've seen, establishing a fiction that works to place himself at the scene of a nativity that obviously occurs 1600 years and change before his own birth.

我们也看到了，他创建了一个虚构的景象,把自己放进了基督诞生的幻景中,而这些比他出生早1600年发生并不断在改变。

耶鲁公开课 - 弥尔顿课程节选

Testifying before the House Financial Services Committee, Federal Reserve Chairman Ben Bernanke said this must change.

VOA: standard.2009.10.01

The Greek way of looking at things requires a change from the characteristic way of knowing things before the Greeks, that is to say, the use of faith, poetry, and intuition.

希腊人观察事物的方式需要改变,这和之前人们通过信仰,诗歌和直觉来了解事物的方式,发生了很大的变化

耶鲁公开课 - 古希腊历史简介课程节选

Clinton,who insisted India can make emission cuts without harming its economy, said she is optimistic the two governments can reach a common approach before the world conference on climate change in Copenhagen in December.

VOA: standard.2009.07.20

Or it can the kind of change we talked about before, where during division there are some chemicals that are trapped in one cell and not in the other, and that could lead to a difference we already talked about.

可能是我们之前说过的,在分裂过程中可能发生的,不对称分裂的现象,并导致我们已经讲过的某些不同

耶鲁公开课 - 生物医学工程探索课程节选

But it costs money," The report comes in the lead up to the December meeting of the Copenhagen Climate Change Conference, to agree on a new climate pact before the end of the Kyoto Protocol in 2012.

VOA: standard.2009.09.01

I want to make one other point before we launch into that, and that is the following: that composers use the rate of harmonic change-- whether it's changing or not changing-- to sort of make us feel different ways about the music that we are listening to.

在此之前我还要说一个问题，不管和声有没有改变，作曲家都能通过和声改变的频率-,让我们对所听的音乐有不同的感受-,它能让我们感受到这段音乐。

耶鲁公开课 - 聆听音乐课程节选