an ace up your sleeve
US /ən eɪs ʌp jʊər sliːv/
UK /ən eɪs ʌp jʊər sliːv/
1.
一張王牌, 秘密優勢
a secret advantage or resource that can be used when needed
:
•
The politician had an ace up his sleeve for the debate.
這位政客在辯論中留有一張王牌。
•
She always keeps an ace up her sleeve for negotiations.
她總是在談判中留有一張王牌。