exercise 既可当动词也可当名词用,都是“运动、锻炼”的意思.
It is important to our health that we spend some time to exercise every day.
我们每天花点时间锻炼对我们的健康是很重要的.(这里exercise 做动词用）
Riding bicycles,swimming are both good exercises.
骑自行车和游泳两种都是很好的运动.