1.   The weather became warmer.

2.   The weather was becoming warmer.

3.   The GISS model predicts increases in yields as summers become warmer in temperate regions, while the Met Office model predicts declining harvests in North America in particular.

4.   Although full membership for Turkey is still a distant prospect, the tone of statements from both sides has become much warmer since the quake.

5.   And while the air seems brownest in winter, by the end of February nights become warmer, the sky turns bluer and trees and plants explode with color.

6.   El Nino occurs when waters off South America become warmer than normal, changing weather patterns around the world.

7.   Gusty winds from the west will descend the east slopes of the Rockies causing the air to become much warmer.

8.   In response, the dark bark of deciduous trees absorb greater amounts of radiation and become warmer.

9.   It will become warmer in the Midwest as winds begin to blow from the south again.

10.   Snow surrounding trunks, despite reflecting visible light, readily absorbs this infrared radiation, becoming warmer itself.