Why doesn’t the air remain still? The reason is that air,
when it becomes heated, becomes lighter and rises. When it rises, other air
moves in to take its place. The temperature of air becomes like the surface of the
earth over which it travels. Over dry land, the air can become very hot. Then,
when the sun goes down, it cools off quickly. Over water, the air heats up more
slowly and cools off more slowly too. These changes cause the movement of air,
which we call wind.
1.
This story is mainly about ___
1.
Air over dry land.
2.
The heating up of air.
3.
How air becomes lighter.
4.
Why air moves.
2.
As air heats up, it __
1.
Cools off quickly.
2.
Becomes lighter.
3.
Becomes very hot.
4.
Blows gently.
3.
Over dry land, the air ___
1.
Heats up and cools off quickly.
2.
Only heats up quickly
3.
Only cools off quickly
4.
Is still.
4.
Wind -
1.
Is the movement of air?
2.
Causes the air to heat up.
3.
Cools off more slowly.
4.
Is hotter over water.
Answer:
1.
4
2.
2
3.
1
4.
1
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