on the ball

漢語翻譯

例句：

1. The new clerk is really on the ball. He's already improved the filling system in the office.
   新來的辦事員真能幹，他已經改進了辦公室檔案歸檔的方法。
2. If you don't get on the ball and start studying harder, you're going to flunk.
   如果你不積極進取，更加努力學習，你就會考不及格的。
3. The new publicity manager is really on the ball.
   新的宣傳部主任確實很內行。
4. The great value of Jack as a committee man is that he is always on the ball.
   作為一名委員，傑克的巨大作用是始終保持警惕。