exercise什么时候家s,举例说明

1.作可数名词用,“练习,习题,体操,功课,操练”等,常用复数.
I'm doing my exercises.我在做练习/功课.
Doing morning exercises is helpful to our health.做早操对我们的健康是有益的.
You should do more spelling exercises.你应该做更多的拼写练习.
2.作不可数名词用,“锻炼,运动”.
You are weak because of the lack of exercise.你身体弱是因为缺少锻炼.
Take more exercise,and you will be healthy.多多锻炼,你会健康的.
3.作动词用,“训练,锻炼”.
You must exercise yourself in order to be stronger and healthier.为了更健康更强壮,你必须锻炼自己.
They are exercising troops.他们在练兵.
You don't exercise enough.你锻炼不够.［作不及物动词］
作动词用还有“履行职责,行使全力”等意思.
You must exercise your own duty.你必须履行你自己的职责.