网友是不是搞错了？exercise 指“体育锻炼”，是可数名词，而且多用复数 exercises，表示各种各样的体育锻炼。

N-COUNT 锻炼;练习 Exercises are a series of movements or actions which you do in order to get fit, remain healthy, or practise for a particular physical activity.

考虑问题，不要想当然，为何不查阅词典呢？