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.    You have no mobile phone. What should you do? Well, next time take a GPS with you. This invention may be able to help you.     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.    We also find GPS devices in cars, planes, or boats. Some of these devices have electronic maps, so you know where you are.   
Some people think that in the future the GPS will be as common as the mobile.     here are also new uses for the GPS. Perhaps they will become like watches. Everyone will have one and you will never be lost again.

A:It is a device(装置) which uses satellites to find the user’s position. B: For example, in a city they can tell you the name of the street. C:It is night and it is cold. D: There are three parts to the Global Positioning System. E: You can hold it in your hand, or put in your pocket. F:They are becoming cheaper and more and more accurate(精确的).