I became a distraught, worried mother, a useless role if ever there was one.

如果有个心烦意乱、忧心忡忡的母亲，一个完全无用的角色，那就是我。

《柯林斯英汉双解大词典》

I was conned into buying a useless car.

我上当受骗买了辆不能用的汽车。

《牛津词典》

This is such a useless device…

这个设备真是没用…

youdao

But Mr. Mindon was proud to be rich enough to have a perfectly useless room in his house.

VOA: special.2009.01.31

I think for the moment it should be plain to you that this is a good way of understanding what the difference between a useful preconception and a useless preconception brought to bear on an interpretative act might consist in.

我想大家现在都能够,从这个例子中明白,解读中有益先见,和无益先见,之间的区别了。

耶鲁公开课 - 文学理论导论课程节选

If you just scramble a sentence, it's pretty useless because the recipients are never going to be able to reverse the process.

如果你只是加密一个句子，这是毫无用处的,因为收件人没法将这个句子,反加密出来。

哈佛公开课 - 计算机科学课程节选

And 18-year-old Simoti Majhi struggles through life with a hunched back and a useless right hand.

CNN: NUCLEAR FALLOUT

We were left holding a useless piece of paper, and it's difficult to enforce a contract there.

FORBES: Magazine Article

There is a useless machine battling another useless machine, turning each other on and off, over and over.

WSJ: Looking for Something Useful to Do With Your Time? Don't Try This