All our advice was dud to him.

对他来讲，我们所有的劝告都是没用的。

The duds were piled up in the warehouse.

那些没用的东西都堆放在仓库里。

The old man realized the next day that he had been dudded.

这个老人第二天才意识到自己被骗了。

He replaced a dud valve.

他换掉了一个无用的电子管。

The mine was a dud.

这颗雷是颗哑雷。

The pivotal circular is a dud.

至关重要的炮弹总是哑弹。

One of these terrors is a dud.

必有一种情况是假的。

The crucial round is a dud.

至关重要的炮弹总是哑弹。