第122页 - 学习与评价八年级英语译林版江苏凤凰教育出版社

Weather comes from the earth's atmosphere and the sun's heat.

Air.

Hot air rises, leaving a space behind.Cooler air goes into that space.

The water vapour in clouds cools and becomes raindrops.The raindrops get bigger and heavier

until they fall from the cloud.

If the temperature is below freezing,tiny bits of ice called crystals form in a cloud.When ice crystals

fall and stick together,they become snowflakes.

D

B

D