ball是可数名词。
ball:n.球;球状物;踢出(或击出、投出等)的一球
We're going to the ball game.
我们要去看棒球比赛。
He couldn't find his magic touch with the ball today.
他今天施展不出神奇的踢球技巧。
A group of kids were playing with a ball in the street.
一群孩子在街上玩球。