They remind him that he booked them once before.

VOA: special.2009.03.09

Alright, so maybe a little underwhelming and we saw already what this program is going to do but let's just go through this process once before we start doing more interesting things and then we'll come back and at least give you a hint of what some of these syntactic details are doing.

好吧，这个程序也许太平庸了，让人印象不够深刻,我们也知道这个程序是干嘛的,在我们开始更有意思的事情之前,让我们再来讨论一下整个过程后再回来,这些语法细节到底是在做什么呢？,先给你们一点小小的提示。

哈佛公开课 - 计算机科学课程节选

Now we worked through this just a little bit once before.

那我们比以前在深入一点

耶鲁公开课 - 聆听音乐课程节选

That's why I must decide on something at once while there is still time, before I am famous.

VOA: special.2009.09.20

We did this once before in this class.

我们在前几讲里用到过这些知识

耶鲁公开课 - 博弈论课程节选

Her grandmother once said that Celia could sing before she could talk.

VOA: special.2009.04.19

So before, because of all these anti-business rhetoric, once you start intervene, s not just the question of the merit of the particular intervention, s the fact that nobody knows ll be intervening again.

所以之前，因为反商业言论，一旦你开始干预，问题就不仅仅在于，it’,某一桩干预事件的好处，而是没人能预料，it’,政府何时又会出手，when，you’

斯坦福公开课 - 经济学课程节选

Once published, the provisional lists will have to be agreed upon by all political parties before ballots are printed.

VOA: standard.2009.09.29

Notice that once we've deleted the dominated strategies, you know I had said before about four people chose this strategy, and in here, about four people chose this strategy, but in this range 30 through 45, I had lots of people.

注意,一旦我们剔除了劣势策略,我们已知有四人选择了,在45到67之间的数,但是选择30到45的有不少

耶鲁公开课 - 博弈论课程节选