1. Be in the air 将要发生的事情
Example: From the arguments going on at the meeting, it seems that a change in policy is in the air.

2. Clear the air 消除误会
Example: We had a meeting with the workers, and I think we’ve cleared the air now.

3. Cost an arm and a leg 极其昂贵
Example: I love that fur coat. However, I don’t think I’m going to buy it because it costs an arm and a leg.

4. A bad egg 缺乏道德的人
Example: You mustn’t lend Tim money, he’s a bad egg. You’ll never see him or your money again!

5. In the Bag 稳操胜券
Example: We have the deal in the bag. The client came in this morning to sign the agreement.

6. In the balance 未知的,不可预测的
Example: His career as a pilot is in the balance, as his eyesight does not seem good enough.

7. Drive a hard bargain 极力讨价还价
Example: Amanda is negotiating the best price from the suppliers. She drives a hard bargain.

8. Ring a bell 看上去或听起来非常熟悉
Example: That face rings a bell, where have I seen him before?

9. Tighten one’s belt 节衣缩食
Example: Now you are out of work, you’ll have to tighten your belt and give up buying new clothes and going out so often.

10. Be in a black mood 情绪极差
Example: My father has been in a black mood for days, we dare not say anything to him.

来源：英语角