Didn't want to go to school." Bullying is defined as negative behavior repeated over time against the same person.

VOA: special.2010.04.22

But she wrote that women's roles decreased over time as the Cherokee people accepted the values of the larger American culture.

VOA: special.2010.04.09

It gets worse over time. The disease affects a small area of cells in the middle of the brain.

VOA: special.2009.04.07

He told her his ideas about how species evolve over time -- what he called the transmutation of species.

VOA: special.2009.02.25

Readers can better understand how informed consent and the question of morality in medical experiments have changed over time.

VOA: special.2010.07.21

Volcanic activity broke the large island into pieces that came to the surface of the sea over time.

VOA: special.2009.12.16

Charles Darwin developed the theory of how living things develop from simpler organisms over long periods of time.

VOA: special.2009.02.25

Rosalyn Schanzer brings to life the clues that suggested to Darwin that living things evolve, or change,over time.

VOA: special.2009.02.27

Studies have shown that over time, most humans need eight to eight and a half hours of sleep for the best health.

VOA: special.2009.08.26

The number of mutations over time helped the team estimate when the duplications in soybeans took place.

VOA: special.2010.02.02

Calhoun said that for a long time he had believed that the dispute over slavery -- if not settled -- would end in disunion.

VOA: special.2009.03.26

At the same time,courts have ruled against any publicly supported celebrations of one religion over another.

VOA: special.2009.12.24

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

VOA: special.2010.07.28

Some experts suggest taking pictures of moles and dating the images to compare over time.

VOA: special.2010.07.06