exercise什么时候可数什么时候不可数？主要分两种情况：

1.exercise

泛指“锻炼”时，做不可数名词，如：take exercise 锻炼身体 take more exercise多锻炼

2.exercise

表示“体操”或“练习（题）”时是可数名词，要用复数形式。如： do morning exercises（做早操），do eye exercises(做眼保健操),do English exercises(做英语练习)

exercise不可数名词的用法

1. (身体或脑力的)活动，锻炼，运动

(1) Swimming is good exercise.

游泳是有益的运动。.

(2) I don' t get much

exercise sitting in the office a11 day.

我整天坐在办公室很少运动。

(3) The mind needs exercise as wel1 as the body.

大脑同身体一样需 要锻炼。

2.行使;运用;使用

(1) the exercise of power by the government

政府权力的行使

(2) the exercise of di scretion

自行决定权的行使