11 及时
12 Don't speak too soon.
12 别说的太早
13 There's no such thing as a free lunch.
13 天下没有免费的午餐
14 without batting an eyelid
14 眼睛眨都不眨；泰然自若
15 know the ropes
15 知道学习规则或内容
16 pay through the nose
16 花很多钱
17 sell like hot cakes
17 很畅销
18 What's done is done.
18 做了就做了
19 Look before you leap.
19 三思而后行
20 When the chips are down.
20 在重要关头；到了关键时刻