解答
解答
It hasn’t any wrong in this two sentence, but you should focus on the timing.
If you have no idea what do they play, you should use the below. If you understand they are playing some ball games, then you should use the above.
Moreover, if you focus on what do they choose, you can using ‘which sport...’
您的問題解決了嗎?
看了這個問題的人
也有瀏覽這些問題喔😉

分かりやすい解説、ありがとうございます!