There we go. Now if I do this, an infinite number of times, we should get roughly 50/50, but now we have the ability to do things only once in awhile.

开始，如果我们，不停地按这个按钮，我们大致会有一半的机会听到猫叫，但是我们每次只有一次按按钮的机会。

哈佛公开课 - 计算机科学课程节选

And then other people are really excited because it's a once-in-a-lifetime opportunity

而另外一些人真的很兴奋，因为这是一个一生只有一次的机会，

正准备奥运会 - SpeakingMax英语口语达人

It's nice, though, only in that it will give us an opportunity to fill in the blank.

这是美好的，虽然，只有在那个里面它才会给我们一个机会,来填充那个空白表格。

哈佛公开课 - 计算机科学课程节选

and they should only make investments if there's really a--if they can see a really compelling case.

他们应在只有在,非常好的机会出现的时候,才进行投资。

耶鲁公开课 - 金融市场课程节选