Imagine the situation. You are driving along 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 (卫星) to find the user’s position(位置). It can find your position to within 20 metres. A
GPS cannot start your car, but at least you will know where you are.
GPS, which means Global Positioning System, is a small
radio receiver. It looks like a mobile phone. You can hold it in your hand, or
put in your 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(计算) 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.
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 countries
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 the 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.