Its reddish color and changes in brightness over time make the planet an unforgettable sight.

VOA: special.2010.07.28

Over long periods of time, these small changes result in the creation of new species.

VOA: special.2009.12.01

Their appearance changes endlessly with the light,the time of year, and the weather.

VOA: special.2009.10.07

After a long time, some of the rock changes to clay.

VOA: special.2009.09.14

When the Food and Drug Administration does issue new limits on salt, the changes on the menu and on grocery food labels will take time to implement.

VOA: standard.2010.04.22

The G20,which includes major industrialized powers in the Group of Eight plus developing nations with significant economies such as China and India, agreed to a specific time line for deficit reduction, while giving governments flexibility to adjust the pace of changes based on their own situations.

VOA: standard.2010.06.27