Imagine the situation. You are driving along in a desert or on a mountain. You have no idea where you are. You passed the last house two hours ago. Then your car breaks down. It is night and it is cold. You have no mobile phone. What do you do? Well, next time take a GPS with you. This invention may be able to help you. It is a device(装置) which uses satellites to find the user’s position. It can find your position to within 20 meters. A GPS cannot start your car, but at least you will know where you are.

GPS, which means Global Positioning System(全球定位系统), is a small radio receiver. It looks like a mobile phone. You can hold it in your hand, or put in you pocket. It is sometimes put into a watch or a telephone. We also find GPS devices in cars, planes, or boats. Some of these devices have electronic maps, so you know where you are. For example, in a city they can tell you the name of the street.

There are three parts to the Global Positioning System. The first part is the receiver. You can hold it in your hand, or have it fixed into your car, plane, etc. the second part is a group of satellites orbiting the Earth. The receiver contacts at least four of the satellites and calculates its position. The third part of the system is a network of ground stations. They are all over the world. They control the satellites and make sure they are working well.

Some people think that in the future the GPS will be as common as the mobile. They are becoming cheaper and more and more accurate(精确的). There are also new uses for the GPS. Perhaps they will become like watches. Everyone will have one and you will never be lost again.GPS

1.According to the passage, with the help of the GPS, people _________.

A. can’t be lost in a new city

B. can’t find their way in different counties

C. can learn about the culture of an unknown place

D. can spend the least time getting to another place

2.We can learn from the passage that ___________.

A. there are three parts to the GPS

B. a GPS can’t be put into a watch

C. a GPS can help you start your car

D. the GPS are becoming more and more expensive

3.The underlined word “They” in paragraph 3 means “__________”.

A. Receivers B. GPS devices

C. Satellites D. Ground stations

4.The passage is mainly about ____________.

A. The history of the GPS B. the introduction of GPS

C. the shape of the GPS D. the three parts of the GPS

5.What can we infer(推断) from the passage?

A. All GPS devices have electronic maps.

B. People in many countries will use the GPS for free.

C. The receiver of the GPS contacts at least five of the satellites.

D. The GPS will become more and more common in everyday life.

The London Olympic Games are coming soon. This summer, Chinese sports fans will be able to watch the exciting games in 3-D on CCTV.

When you watch 3-D movies or TV, you have to wear a special pair of glasses. The 3-D glasses make the people and the things on the screen look like they are in the room with you.

3-D, means having three dimensions*: width*, height and depth*. 3-D technology is based on the way the human brain and eye work. Because the pupils of a person’s eyes about 6.5cm apart, when we look at something, each eye sees it from different angle*. Our eyes send the two pictures to our brain, and the brain puts them together. The small difference between the picture from the right eye and the picture from the left eye makes us see depth.

While watching 2-D films, we don’t have to wear the special glasses. We see the pictures in two dimensions, each eye get same information. This is because there is only one way of watching it.

So the aim of 3-D technology is to get a different picture into each eye of the person. It uses two film projects. One projects a left eye picture and the other projects a right eye picture. When we are in the cinema, we can see different pictures in each eye at the same time with the help of the 3-D glasses.

While watching 3-D films, we feel that we are actually in the same environment as the things we are watching. However, some people are against watching 3-D films. One of the reason is the 3-D glasses make the screen of the film or TV look darker. It is bad for eyes. What’s more, people with eye problems may get headaches if they spend too much time watching 3-D movies, because their brains need to work harder to “read” the pictures.

1.The third paragraph mainly tells us _____________.

A. how we see things in 3-D

B. how we watch the Olympic Games

C. how 3-D films are made

D. where we watch 3-Dfilms or TV

2.When we watch a 2-D film, each of our eyes gets ______ information.

A. no B. different C. dark D. the same

3.Which of the following is TRUE according to the passage?

A. We don’t have to wear 3-Dglasses if we watch games in 3-D on TV.

B. The 3-D technology is depended on the way the human ear and eye work.

C. All the people can have fun watching 3-D movies or TV for a long time.

D. 3-D glasses make us see different pictures in each eye at the same time.

4.Why are some people against watching 3-Dfilms? Because ________.

A.they make them more excited or sadder.

B.3-D glasses make the screen look darker.

C.3-D films make all people get headaches.

D.They dislike watching the Olympic Games.

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