You have to have a sharp knife.

你必须有一把锋利的刀。

youdao

You are welcome to the loan of my knife.

你可随意借用我的小刀。

《新英汉大辞典》

That's ill done, Hans, you should have put the knife in your pocket.

那可真糟糕，汉斯，你应该把刀放在口袋里。

youdao

So in the story Dudley is there, pen knife in hand, but instead of the prayer or before the prayer, he says "Parker, would you mind?"

故事里达德利手拿小刀，没有做祷告，或是在做祷告前，他说，派克，介意我们杀你吗“

耶鲁公开课 - 公正课程节选

Then in another corner, you notice that there's a fight and somebody pulls out a knife.

而在另一个角落，一群人争吵起来，有人还亮出了一把刀。

Let's 课堂 - SpeakingMax英语口语达人

Well,I think one of the questions --the question is how can you successfully invest in a market where,I guess, people say you might catch a falling knife.

其中一个问题,提问是,怎么能够成功地,投资于一个,有所谓抄底行情的市场

耶鲁公开课 - 金融市场课程节选

Kieren and Khalid, both 12, said they found it really interesting and learnt that if you are caught carrying a knife you can spend up to 25 years in prison.

BBC: December's practice News Day

We mostly learn that lore in the form of conventions: how you hold the knife, where you put it, that John was the witty Beatle, Paul the winning one, that the North once fought the South.

NEWYORKER: The Dragon��s Egg

"One of the things the public has to understand, an individual wielding a knife at you at about 20 feet can be on top of you in a split second, " he said.

CNN: Video captures Michigan man's shooting by police