You are useless as a worker if your body does not feel great.

如果你的身体感觉不好，你就是个没用的员工。

youdao

Women's tears are useless. But if you make women cry, that mean you are useless.

女人的眼泪固然无用，但如果你让女人掉眼泪，那就是你没用。

youdao

Women's tears is useless liquid, but you let the woman tears that means you are useless.

女人的眼泪是没用的液体，但你让女人流泪说明你很没用。——韩寒。

youdao

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

Lots of theories have been produced to explain this puzzle, but the most plausible answer may be that the premium varies according to the circumstances and the markets' liquidity which is pretty useless if you are trying to make predictions.

ECONOMIST: A survey of global equity markets

Tools that claim to keep you connected to friends and family are obviously useless unless your friends and family also utilize them.

FORBES: Game Over. Here's Why Facebook Wins

Suppose you are like me, and once you fire up your laptop to check your email, you are in danger of spending the whole morning on the Net, doing increasingly useless things.

WSJ: How to Be a Better Procrastinator