You must remember that this describes a particle going side to side.

务必记住,描述的是一个质点的横向运动

耶鲁公开课 - 基础物理课程节选

What that means is that integrated vertically as well as horizontally.

就是指纵向的整体和横向的整体。

哈佛公开课 - 幸福课课程节选

It's also horizontally interconnected.

同样也是横向相互联系的。

哈佛公开课 - 幸福课课程节选