例句：
He dismissed the opinion polls as worthless.
他认为民意测验毫无用处而不予考虑。
Training is worthless unless there is proof that it works.
训练并无价值，除非证明其有效。
An agreement is worthless till our name is written with a pen.
除非用笔把我们的名字写下来，否则协议毫无价值。
The closure left 500 people jobless.
这次倒闭使500人失业。
They joined the ranks of the jobless.
他们加入了失业大军。