And for those of you who want to pick up a more sophisticated text editor, we will point you in the direction soon of tools called Vim, or Vi, Emacs.

如果你们有谁想使用,更高级点的文本编辑器的话，我们可以给你们,一些指导：像Vim，或者Vi，Emacs编辑器。

哈佛公开课 - 计算机科学课程节选

At each point, er is a different vector pointing in the radial direction of length one.

矢量 er 在每一点处都不同,方向都从圆心指向该点,模长为1

耶鲁公开课 - 基础物理课程节选