43.
题目
43.
Satellites are an important part of our ordinary lives.For example,the information for weather forecasts is sent by satellite.Some satellites have cameras which take photographs of the Earth to show how clouds are moving.Satellites are also used to connect our international phone calls.
Computer connections of the World Wide Web and Internet also use satellites.Many of our TV programs come to us through satellites.Airplane pilots also sometimes use a satellite to help them find their exact location.
We use satellites to send television pictures from one part of the world to another.They are usually 35,880 kilometers above the equator.Sometimes we can see a satellite in the sky and it seems to stay in the same place.This is because it is moving around the world at 11,000 kilometers an hour—exactly the same speed that the earth rotates.A satellite must orbit the Earth with its antennae (天线) facing the Earth.Sometimes,it moves away from its orbit,so there are little rocket
答案
1.C
2.B
3.A
4.D
5.D
举一反三
已知函数f(x)=x,g(x)=alnx,a∈R.若曲线y=f(x)与曲线y=g(x)相交,且在交点处有相同的切线,求a的值和该切线方程.
我想写一篇关于奥巴马的演讲的文章,写哪一篇好呢?为什么好
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