文章细节：liuxuepaper.com 发表时间：2010-11-29
Air is all around us. It's around us as we walk and play. From the time we were born, air was around us on every side. When we sit down, it is around us. We live in air.
All living things need air. Living things can't live without air. We can go without food or water for a few days but we can't live for more than a few minutes without air. We take in air. When we are working or running, we need more air. When we are asleep, we need less air.
We live in air, but we can not see it.
We can only feel it. We can feel it when it is moving. Moving air is called wind. How can you make air move? Here is one way. Hold an open book in your hands in front of you. Close it quickly. What can you feel? What you feel is the air.
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