「锦囊妙计」英文怎么说？

(have an) ace up one's sleeve 

锦囊妙计、手中有王牌、有获胜的绝招、有好的办法

Unless you have an ace up your sleeve, we're going to lose the game. 

除非你有什么王牌绝招的，不然我们这场比赛是输定了。

I've got an ace up my sleeve, and it should solve all your problems. I'll tell you what it is after I get promoted. 

我有一个好办法，它应该可以解决你所有的问题，等我升职后才告诉你。