be on the ball
机智、聪明或反应敏捷
口语·形容机警能干或反应快
英文释义
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.
典故来源
源自棒球或篮球运动，指球员时刻准备接球或投篮，比喻反应迅速、注意力集中。