the trouble with exercise is that it works well only if he or she is interested in it

the trouble with exercise is that it works well only if he or she is interested in it

运动的问题在于,一个人必须愿意运动才会行得通

这些练习的问题在于：只有当人们对它有兴趣时，它才会表现的很好。

运动的问题在于：只有一个人对运动感兴趣了，运动才有效果