n.潜艇；替代品
vi.替代
vt.转包合同
Local radio reported that the sub had oxygen tanks. 当地广播报导，这艘潜艇内配备氧气桶。
The nuclear-powered submarine can overrun any other sub. 核动力潜艇能比其他任何潜艇驶得快。
I had to sub for the referee, who was sick. 裁判病了，我得代为裁判。
Clive Walker came on as a sub and starred. 克里夫-沃克替补上场，大放异彩。
