ace in the hole

• n. 最后的王牌；最后王牌

ace in the hole的用法和样例：

例句

用作名词 (n.)

1. That spare can of gas in the trunk was our ace in the hole.
   后备箱里那罐剩余的汽油是我们最后的王牌。
2. The coach saved his star player for a trump card.
   教练保留他的明星选手，作为他的王牌。