be on the ball
機智、聰明或反應敏捷
口語·形容機警能干或反應快
英文釋義
to be alert, attentive, and well-prepared; to be quick to understand and react
例句
You need to be on the ball during the meeting to catch every detail.
典故來源
源自棒球或籃球運動，指球員時刻準備接球或投籃，比喻反應迅速、注意力集中。