The pistons go up and down as a person stands on lever devices treadles and uses a natural walking motion.

VOA: special.2009.08.17

He learned to get light to go far enough down a glass fiber to pass on signals.

VOA: special.2009.12.08

But if this oil gets on there, everything we got invested, we just going to go down."

VOA: standard.2010.05.04

Main said the government is now willing to go directly to court to shut down mines when necessary, and he called on Congress to enact tougher enforcement measures.

VOA: standard.2010.04.27