have something up your sleeve
成語所屬單字sleeve
have something up your sleeve — 慣用語
1. to have a secret plan, idea, or piece of information that you keep hidden so tha
1.慣用語
釋義
另有妙計；留有後手
to have a secret plan, idea, or piece of information that you keep hidden so that you can use it later to gain an advantage.
例句
The other team seemed confident, but our coach had a surprise strategy up his sleeve.
I do not know what Amira has up her sleeve, but she seems very sure the plan will work.