1.throw the book at sb.
从严处罚某人
例句：If you get caught they'll throw the book at you!
    如果你被抓住，他们会从严处罚你的！

2.let your hair down
使某人放松（尤指辛劳过后）
例句：Visitors let their hair down and enjoyed the show.
    游客们都放松下来，尽情观赏演出。

3.sweet tooth
爱吃零食
例句：Do you have a sweet tooth?
    你爱吃零食吗？

4.turn the tables
扭转局面
例句：The tables were turned in the second half.
      下半场比赛，整个局势都扭转了。

5.dog days
盛夏，酷暑期/艰难时刻
例句：Few opera houses survived the dog days of the 1980s.
     没有几家歌剧院捱过了20世纪80年代的萧条期。

6.take sth. with a grain of salt
对某事半信半疑，有所保留
例句：Most of what he says should be taken with a grain of salt.
     他的话大部分都值得怀疑。