The reason it looks like a tautology, because you look around, nothing seems to have its velocity forever.

其原因听起来像是绕圈子,因为你看看四周,似乎一切都不可能永远运动下去

耶鲁公开课 - 基础物理课程节选

In the famous battle of Marathon, which I will tell you about when we get there, one of its features is that because the Greeks were numerically badly inferior to the Persians, they had this problem of covering the line.

比如在著名的马拉松战役,迟些我们会讲到,马拉松战役中,希腊军队,在人数上远不敌波斯军队,这为布阵造成很大的困难

耶鲁公开课 - 古希腊历史简介课程节选

So this is a monomer or a single unit from an RNA molecule, you know that because it's ribose and it's the particular molecule that has as its organic base.

所以这是一个RNA单体,即RNA上一个单独结构单位,你通过核糖,和碱基就能够确认它是RNA,这个RNA单体的碱基为A

耶鲁公开课 - 生物医学工程探索课程节选