The coral whitens when it becomes stressed by warmer temperatures and expels the algae organisms it needs to survive.

VOA: special.2009.04.22

An assistant professor who receives tenure becomes an associate professor and may later be appointed a full professor.

VOA: special.2009.04.09

Clay becomes very hard when it is put in a fire or a special oven called a kiln.

VOA: special.2009.01.12

Some people worry that officials could take their land if it becomes polluted by oil in a storm.

VOA: special.2010.06.04

This becomes a sheet of paper. Large machines started to be used for making paper near the end of the sixteenth century.

VOA: special.2009.07.06

In the United States, there are now policies for the use of H1N1 vaccine when it becomes available.

VOA: special.2009.08.18

In the United States, there are now guidelines for the use of H1N1 vaccine when it becomes available.

VOA: special.2009.08.05

The IdeaPad U-One Hybrid is a notebook computer, which has a removable screen that becomes a digital tablet.

VOA: special.2010.01.26

So,smaller cultures lose their local language as the language of the culture in power becomes the stronger influence.

VOA: special.2009.12.02

But by the end of the movie, she has a chance to let her acting skills shine and she becomes a star.

VOA: special.2009.09.20

today,after all the votes have been tallied, health insurance reform becomes law in the United States of America.

VOA: special.2010.03.24

However,snow can become hard and flat as it becomes older or if there have been strong winds.

VOA: special.2010.01.05

Not surprisingly, how a parent acts may also influence whether or not a child becomes a bully.

VOA: special.2010.05.06

The World Health Organization will not declare an influenza pandemic unless a virus becomes widespread in at least two areas of the world.

VOA: special.2009.05.06