题型：阅读选择 题类：模拟题 难易度：普通
In the picture on the right, it seems that Line AB is shorter than Line CD, but in fact Line AB is as long as Line CD. Which paragraph can explain what has happened to our eyes?___________
Man has invented four kinds of satellites(人造卫星).
The first kind of satellites studies the geography of the earth. They are used to make maps. They also help countries to see where they may find oil or gold. |
The second kind of satellites is used to guide ships and planes. A ship or a plane can send a message to the satellite, and the satellite can find out where the ship or the plane is. |
The third kind studies the weather. These satellites watch clouds and strong winds moving across the earth. They warn countries to make preparations when very bad weather is coming. |
The last kind is used for communications(通信). Telephone calls between countries can be sent. by these satellites. Some can carry hundreds of calls at the same time. The call is sent to the satellite, then the satellite' sends it to a station in the country and this country is being phoned. These satellites also carry pictures; they can receive and send about eight programmes at a time. |
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