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

VOA: standard.other

I could take an unknown gas and put it in and measure it and then say, wow, those are the lines that are characteristic of sodium.

我取一种未知气体，把它放到管里,然后检测它，哇，这些线是钠的特征。

麻省理工公开课 - 固态化学导论课程节选

Therefore, it'll compress by an unknown x, which is equal to mg divided by the force constant of the spring.

因此它的压缩量为 x,也就等于 mg 除以弹簧的弹性系数

耶鲁公开课 - 基础物理课程节选

Afghan and NATO officials say that Taliban insurgents in the northern Kunduz province were driving two hijacked fuel trucks to an unknown destination when fighter planes located them on a river bank and bombed them.

VOA: standard.2009.09.04

The mathematical theory of probability was unknown until that time and you can see that insurance suddenly made an appearance at that time.

在那之前,概率的数学理论,是不存在的,而随着概率论的出现,保险业也突然出现了

耶鲁公开课 - 金融市场课程节选

I want to see you back at the end of this trip covered in mud!'" Other dads in Feiler's Council of Dads include the man who helped Feiler get published back when he was an unknown writer.

VOA: standard.2010.06.19

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

So an astronaut on the flight of Gemini Four, Ed White,took that first frightening step into the unknown.

VOA: special.2009.07.01

The exact cause is unknown. But in a recent study, an experimental drug showed signs of halting the disorder in laboratory mice.

VOA: special.2010.05.19

If hoarseness continues or the cause is unknown, doctors should perform an examination called a laryngoscopy.

VOA: special.2009.09.02

An inquest takes place when someone has died under suspicious or unknown conditions.

VOA: special.2009.08.31

"You can have that test, but it can't be an exclusive test because of the nature of the patent laws which are to protect new and unknown inventions."

VOA: special.2010.07.16