a bad penny

例句：

1. 1. Hefound a bad penny on the ground anddecided to keep it as a lucky charm.
   他在地上发现了一枚坏钱，决定把它作为幸运符保留。
2. 2. Theold man kept a badpenny in his pocket for luck.
   老人把一枚坏钱放在口袋里以期运气好。
3. 3. She gave away allher bad pennies to buy a newdress.
   她把所有的坏钱都捐出去买新裙子了。