1.Poker face 脸上毫无表情，不动声色
I tried to keep a poker face even though I was scared to death when I went back to my doctor to hear the results of my lab tests.
2.Wild card 无法预料的事，未知数
The wild card in the picture is eastern Europe.
3.Close to the vest 做事小心谨慎
The board members, resolved to play their cards close to the vest, made no public statements after the meeting.
4.Play with a full deck 有头脑的，神志清醒的
Have you noticed that old man who sits on a park bench all day talking to himself? I overheard him today and he's just talking nonsense. I'm afraid the poor guy isn't playing with a full deck.
5.Holding all the cards 处于非常强势（或有利）的位置
Which politician would dare tell the people that they should not hold all the trump cards in foreign policy or environmentalism?
6.Have a good hand 拿到一手好牌，有成功的可能，占上风
I must complain the cards are ill shuffled till I have a good hand.
7.Tip one's hand 露底牌，暴露自己的意图；（疏忽地）泄露秘密
Don't let the landlord hear that I don't have any other options. I don't want to tip my hand when we negotiate over the price.
8.Lay (or put) one's cards on the table 摊牌，开诚布公地说明事实，和盘端出
I don't want to keep any secrets from you. So, I'm going to lay my cards on the table and tell you that I'm no millionaire, and that if you marry me, you'll have to work for a while - at least until my business starts to grow.