ot 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 cannot see it. We can only feel it when it is moving. Moving air is called wind. How can we make air move? Here is one way. Hold an open book in front of your face， close it quickly. What can you feel? What you feel is air.
Passage 29.Clocks
There are many clocks in the Brown’s house. They are in different rooms.A big clock stands in a corner of the sitting room. It is a very， very old clock， but it still keeps good time. Mr. Brown winds it once a week.
Passage 30. Swimming
Swimming is a good sport. It’s popular. People like swimming because the water makes people feel cool. But if they swim in a wrong place， it is very dangerous. These years， some people died when they were enjoying themselves in water and most of them were students. Summer holiday will be there again. I want to give you some advice. First， don’t get into the water when you are alone. Second， don’t get into the water if there is a No swimming sign. Third， you should be careful in the water. If you remember these， swimming will be safe and it’s good for your health.
Modern Technologies
We’re all enjoying the conveniences and happiness brought by modern technologies. We use telephones and mobile phones to call， emails to write and vehicles to drive； we go to another country by air planes； we see what is happening in the world by TV programs and Internet， and we even watch sports games on live. Nowadays， without these technologies， I can’t imagine what my life could be.
I used to read an article describing the modern lives of human beings. It says we will have many phone numbers if we want to search for one person； we send emails and cell phone messages to our friends in stead of visiting them. More and more people would rather sit in front of a computer than a TV. And we seldom go