One of easiest ways to keeo (正确拼写：keep) fit is to do jogging.
译文：慢跑是最简单的减肥方法之一.
keep fit是有“保持健康”的意思,但在这里是作“减肥”的意思.
Jogging is the name for a very gentle running.
译文：慢跑是一种很温和的跑步的名称.
It is just a little faster than walking.
译文：它只比步行快一点点.