The professor wanted to see if the animals could tell the difference between the calming music and the music written to make them uneasy.

VOA: special.2009.09.29

"The nicest thing is you can still see their colors. There's enough contrast so that you can tell the difference between a red star and a blue star and show people that stars have colors.

VOA: special.2009.10.27

"You think you've got your own computer all to yourself and you can't tell the difference that you're working on something other than a computer and sharing this other resource and doing it at a much lower cost than having your own PC."

VOA: special.2010.04.12

"In recent years,these companies have become much more sophisticated, up to the point where it's impossible to tell the difference between the counterfeit cigarettes and the actual cigarettes."

VOA: standard.2010.08.11

This week on our program, we tell you about three people who are working to make a difference in the world.

VOA: special.2010.05.03

Today we tell about 4 more individuals who are making a difference in the city of Washington, D.C.

VOA: special.2009.01.28