Definition
To possess a hidden advantage or secret plan that can be used when needed.
持有锦囊妙计
She agreed to all the terms in the negotiation, but I felt she had a card up her sleeve.
她同意了谈判中的所有条件，但我觉得她还有秘密武器。
We thought they were out of options, but they pulled out a card up their sleeve at the last moment.
我们以为他们已经没有选择了，但他们在最后一刻亮出了秘密武器。
Don't worry, I still have a few cards up my sleeve that will surprise them.
别担心，我还有几张王牌，会让他们大吃一惊。