Five or six gunshots were fired by an unknown, would-be assassin.

VOA: standard.other

- "She lived unknown and few could know"-- how can she be unknown if few know anything about her?

她不为人知地活着，鲜有人知道她“,如果有任何人知道关于她的任何事情,又怎么能说他不为人知呢？

耶鲁公开课 - 文学理论导论课程节选

So, what we have found out so far, I'm purposely going from x to y because I want you to know that the unknown variable can be called an x or can be called a y.

到目前为止,我们有这些结论,我特地把x换成y,因为我想让你们明白,未知变量既可以写成x,也可以写成y

耶鲁公开课 - 基础物理课程节选