a spent bullet

• n. 强弩之末

例句

用作名词 (n.)

1. When I had made something more than a league of way by the help of this current or eddy, I found it was spent and served me no farther.
   我靠了这股洄流的推动，继续向前走了一海里多，就发现它的力量已经成了强弩之末，再不能有助于我了。