I thought that the negotiations would be unsuccessful but my boss had another card up his sleeve that we didn't know about.
我认为这次的谈判不会成功,但我的老板却有着另一个我们都不为所知的锦囊妙计。
解析:card up one's sleeve(card作名词用哦)解释为锦囊妙计,绝招,王牌等。英语含义为another plan or argument saved for later。
He laid his cards on the table during the meeting to dispose of the excess inventory.
他在会议中摊牌(表明)要解决掉多余的存货。
解析:lay one's cards on the table(also put one's cards on the table)从字面上就可以看出是摊牌的意思,通俗点说就是坦率诚实地表明自己的立场,看法的。英语含义是let someone know one's positions and intentions openly and honestly.