但是有没有一次或几次大移民浪潮是穿过白令海峡到达美洲的呢？

But was there one major wave of migration across the Bering Strait into the Americas, or several?

youdao

她从这儿经过时没有一次不停下来问候一番。

She never passes without stopping to say hello.

《新英汉大辞典》

据我所知，没有一次是成功的。

To the best of my knowledge, none have been successful.

youdao

To some extent, the subprime crisis is a failure of Basel II, which is not even fully born yet.

从某种程度上讲,次贷危机就是新巴塞尔协议的一次失败,该协议甚至还没有正式生效

耶鲁公开课 - 金融市场课程节选

It was the first time I actually I've never got into a church in my kind of modern Presbyterian church in Madison, you know in Wisconsin where I grew up.

那真的是我第一次感受到,我从来都没有在,麦迪逊去过现代的长老会教堂，你们知道吧，我是在威斯康星洲的麦迪逊长大的。

普林斯顿公开课 - 人性课程节选

And I'll also remind you, and we're going to see this in the next example, we talked about looking at the worst case behavior. In these cases there's no best case worst case, it's just doing one computation.

我还要提醒大家的就是，我们也会在下一个例子里发现者一点，我们谈到了要去考虑最坏的情况,在下面这些例子里,没有好情况坏情况之分，就只是一次运算。

麻省理工公开课 - 计算机科学及编程导论课程节选