sub

n.潜艇；替代品

vi.替代

vt.转包合同

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。