I hit her such a fourpenny one that I sent her flying.

一拳把她打飞。

One day,he took me aside and promised me a sliver fourpenny on the first of every month if I would keep my eye open for a sailor with one leg and let him know the moment he appeared.

有一天他把拉到一边，证每月给四，果能留心注意一个只有一条腿的水手，并且在他（水手）出现的那一刻告诉他。