"have on the ball" in Chinese (Simplified)
头脑灵活能干（非正式）
Definition
表示某人在处理任务或解决问题时聪明、机敏且有能力。
Usage Notes (Chinese (Simplified))
非正式用语，多见于美式英语。常用 'have'（有头脑、有能力），形容既聪明又实用的人。正式场合不适用。
Examples
She really has on the ball when it comes to math.
她在数学方面非常**头脑灵活**。
If you have on the ball, you can solve this quickly.
如果你**头脑灵活**，很快就能解决这个问题。
That new student has on the ball; he learns fast.
那位新同学**头脑很灵活**，学习很快。
Wow, you really have on the ball—nobody else got that answer!
哇，你真的**很能干**——没有人答出来！
He might not talk much, but he has on the ball.
他可能不多话，但他真的**很能干**。
Give her any challenge—she has on the ball to handle it.
给她任何挑战——她都**能够胜任**。