阅读短文，掌握其大意，然后从每小题所给的四个选项中选出一个最佳答案。

    Air is all 1 us. It's around us 2 we walk and play. From we were born,(出生) air is 3 around us. When we sit down, it's around us. When we 4 to bed, air is also around us. We live in air.

    All living things 5 air. Living things can't live 6 air. We can go without food or water for 7 days, but we can't live without air. When we are working or running, we need 8 air. When we are asleep, we need air, 9.

    We live in air, but we can't 10 it. We can only 11 it. We can feel it when it is 12. Moving air is called wind. How can we make air 13? Here is one way. Hold an open book in your hands 14 front of your face. Close it 15. What can you feel? What you feel is the air.