But Chad Reissig says scientists do not know a lot about them and how they interact with each other and caffeine.

VOA: special.2009.07.22

She and her best friend still use it, especially when they do not want their children to know what they are talking about.

VOA: special.2009.12.04

Amanda says she does not want children to ever give up because they do not know what they can do until they try.

VOA: special.2009.07.31

And one day you want to go to the cemetery or something, you can't do it because you don't know where they are.

VOA: special.2010.02.01

They do not know why da Vinci painted it, or how it ended up in the collection of French ruler Francis the First.

VOA: special.2010.06.23

The scientists say they do not know how the treatment would work with patients who have no sensation at all below the injury.

VOA: special.2011.06.01

They know that studies show lightning and snakebites hurt more people than do shark attacks.

VOA: special.2011.03.15

They do not know why all these things were found together in one place.

VOA: special.2010.08.03

They can do this by helping individuals they know who may be experiencing loneliness.

VOA: special.2009.12.22

In many cases, people do not want others to know they have a problem.

VOA: special.2010.04.13

They do not know where they are or where they came from.

VOA: special.2009.09.15

They do not know what the purpose of the cave was.

VOA: special.2010.08.03

We are worried because we do not know how long they will stay or how we will take care of them.

VOA: standard.2009.10.27

"I think the more the American people look at this administration's budget, the more they know we can do better,".

VOA: standard.2009.03.17