And I want you to get used to this, that colon is important, it identifies the start, and then the set of indented things identify all the things at the same level, and when we reset back to the previous level, that's when we go back to where we were.

我希望大家熟悉这个结构，冒号很重要，它定义了开始的地方，然后缩进号代表着,同样一层的对象，当我们到了，不缩进的地方的时候，也就到了以前的状态。

麻省理工公开课 - 计算机科学及编程导论课程节选

The nucleotide has a directionality, there's an up and a down to it and it's going to turn out the chain that's formed by polymerizing these has a directionality as well and that's important in defining the structure.

核苷酸有方向性,有上端和下端,核苷酸长链,是由核苷酸沿一个特定方向聚合而成的,这在定义结构时很重要

耶鲁公开课 - 生物医学工程探索课程节选