One more challenge. And that is keep going.

VOA: special.2010.05.28

"Every fish we take out there is one less fish to challenge the electric barrier further upstream yet."

VOA: standard.2010.07.19

Declarations,commitments and speeches don't feed hungry people, He says the scale of the challenge is significant. There are more than one billion poor and hungry people in the world today.

VOA: standard.2010.03.29

One of the most closely watched cases this term will be heard early next year when the high court considers a challenge to gun control laws in the city of Chicago.

VOA: standard.2009.10.05