Pack-year

    Pack-year 指烟民一年间每天抽一包烟，用来衡量抽烟的时间和数量

    例句：

    My friend's father has been smoking for 16 pack-years. It's no wonder he developed lung cancer at his age.

    我朋友的父亲已经有16年烟龄，每天一包未曾间断。难怪在老年的时候患上了肺癌 ......