It's from my boyfriend, if you must know.

倘使你一定要知道的话，这是我男朋友给的。

《牛津词典》

You must know him—he's an institution around here!

你一定认识他—他是这一带的知名人士！

《牛津词典》

It scared the hell out of her, if you must know. And me, too.

这把她的魂都吓飞了，如果你一定要知道的话。而且我也被吓坏了。

《柯林斯英汉双解大词典》

And,children, he says must know and understand their rights, so they can claim them.

VOA: standard.2009.10.08

He must know how to use religious passions and sentiments but not be used by them.

他必须懂得如何利用宗教热情以及,宗教情绪而不是被它们所控制。

耶鲁公开课 - 政治哲学导论课程节选

that after Lolita.) But what I mean is that the reader must know when and where to contribute his imagination, and this he does by trying to get clear the specific world the author places at his disposal.

有些人可能就会那样想）,但我的意思是,读者必须知道何时何地需要发挥想像力,这样以看清作者所设置的特定的世界,在这篇小品文中。

耶鲁公开课 - 1945年后的美国小说课程节选

We should not forget the equally important question of what citizens must know, believe, and do.

CNN: Citizenship isn't about passing a civics test

For peace to endure, Arabs and Israelis must know the calm of a normal life.

CNN: AllPolitics - Clinton-Netanyahu Transcript

But if you must know how the race is going, ask the math geeks.

FORBES: The Election is Over, and the Math Geeks Won.