So you can think of it, if we were to just think of it as a straight line that we were going across, essentially what we're saying is that we're getting from point a to point c without ever getting through point b.

你们可以来想想看，如我我们把它想成是一条直线,我们要沿着这条线经过，这就是说我们要从ａ点,不经过ｂ点而到ｃ点。

麻省理工公开课 - 化学原理课程节选

I could take and draw a line continually down the molecule where my finger was touching; my finger would be touching a phosphate here, the 5' carbon, the 4' carbon, the 3' carbon, and the next phosphate.

我可以画一条这样的线,沿着这个分子不断向下延伸到我指的地方,我指的这一点代表着磷酸基,5' 碳部位,4'碳部位,3' 碳以及下一个磷酸基

耶鲁公开课 - 生物医学工程探索课程节选