题目内容：

When was the last time you relied on an old-fashioned map to figure out the route to an unfamiliar place? For many, the GPS has revolutionized navigation, making a paper map almost obsolete? So how has this piece of technology developed over its 26 years of existence? On February 14,1989,the first satellite in the US Global Positioning System was sent into space from Cape Canaveral, beginning the start of one of the wonders of the modern world.

GPS stands for Global Positioning System, which is made of a network of around 30 satellites that move around the earth. The system uses a process called trilateration to find out one’s position. By measuring the time it takes for the signal to reach one satellite, the GPS can determine your distance from the satellite, creating a sphere(范围) of possible locations. Measuring your distance from at least three satellites will narrow your location to the place where the three spheres cross one another, to the accuracy(精确) of about less than 1 meter!

The GPS was first invented during the Cold War by the United States Department of Defense. In 1960, the first system, which was made of just five satellites, was put into place. It was initially created for strictly military(军事的) use; however, in 1983, as a result of faulty navigation technology, a Korean passenger plane mistakenly flew into USSR territory(苏联领土) and was shot down. In order to prevent such bad events, American President Ronald Reagan allowed civilian(民用的) use of the GPS.

Over the next ten years, the system’s accuracy improved as the network was increased to 24 satellites. And during the first Persian Gulf War, the new GPS was finally used by the military. Now scientists use the technology to track animals to better understand their movement and behavior. Parents who may be worried about their children can also use GPS technology to track them.

1.The underlined word “obsolete” in Paragraph 1 can best be replaced by “     ”.

A. priceless    B. unusual

C. perfect    D. useless

2.The second paragraph is mainly about      .

A. how the GPS works    B. the history of the GPS

C. the applications of the GPS    D. some problems with the GPS

3.According to the text, the GPS     .

A. has a history of over 100 years

B. became popular during the Cold War

C. relies on the satellites circling the earth

D. was available first during space exploration

4.What does the author think of the GPS?

A. It is not always reliable

B. It has a lot of uses in many fields

C. It makes our life more peaceful

D. It will soon go out of fashion