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

VOA: standard.other

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

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