exercise不可数名词的用法：
（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 all day.
我整天坐在办公室很少运动。
（3）The mind needs exercise as well as the body.
大脑同身体一样需要锻炼。
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 discretion
自行决定权的行使