adj.无价值的
n.哑弹；无用的人或物
（复数）duds: 衣服；个人物品.
How can we be expected to carry out our jobs with the dud equipment you gave us? 你怎么能指望我们用这些你给的烂设备来完成工作呢？
用作名词 (n.)This battery is a dud. 这电池是废的。
The new manager is a complete dud. 新经理完全是个废物。
The whole plan turned out to be a dud. 整个计划到头来完全失败了。
Two of the fireworks in the box were duds. 盒子里的烟火有两个是坏的。
