A: Who did the stupid thing?

谁干的蠢事？

B: Maybe it was dick.

也许是迪克。

A: I don't think so. Dick has been on the ball and he never does things like that.

我不觉得。迪克向来出色精明，从来不干这事。

B: Then it must be a naughty boy who did it.

那么一定是哪个调皮鬼干的。

on the ball

警觉的；精明的；能干的

描述一个人警觉和能干

You need to be on the ball if you want to succeed in this competitive market.

如果你想在激烈的市场竞争中成功，你需要保持警觉。

描述一个人对细节非常在意

Make sure you're on the ball during the presentaion—pay attention to every detail.

在演讲过程中一定要保持警觉——关注每一个细节。

描述一个人能快速理解并应对新情况

She's on the ball and quickly identified the potential risks.

她非常警觉，迅速识别出潜在的风险。

Have a ball

玩得开心；过得愉快

We had a ball at the amusement park.

我们在游乐园玩得很开心。

get the ball rolling

开始某事；继续某事

Our time is limited, let's get the ball rolling.

我们时间有限。咱们开始吧！

The ball is in your court

轮到你采取行动了

I've given you all the information you need. Now the ball is in your court.

我已经给你提供了所有你需要的信息。现在轮到你做决定了。