1.各种起到锻炼身体作用的活动是 exercise ，不可数。动词搭配用take.You've put on weight! Better take exercise every day.2.有规律的或有规则的操练只用exercises。如：眼保健操、广播体操等。动词搭配用do.We do eye exercises during the break.3.与知识学习有关的练习是可数名词，有单复数之分。动词搭配用do.Today,I'll give three exercises to do.
当锻炼讲，exercise不可数但是如果是具体的锻炼，如一节操，一道题，则exercise可数，就可以加sexercise 一般用法： take exercise, do morning exercises orning exercises特殊用法： 表示体育锻炼时不可数；表示练习时可数do exercise 是不可数名词，表示进行体育锻炼，或锻炼身体do exercises是可数名词，表示做练习或作习题，比如学习上或优育上或音乐等方面的练习如：He always does exercise in the morning. 他经常晨练。He always does some exercises in the morning. 他经常早上作练习（习题）
