【答案解析】In many parts of the world the weather is very changeable, and it plays an important part in the daily lives of the people. If they are farmers, fishermen, or sailors, for instance, they need to know about weather changes in advance. Space scientists and airplane pilots especially need weather information. Since ancient times, men have observed the sky, the wind, and the atmosphere, as well as a variety of other weather signs, in order to make weather predictions. But often their weather predictions have not been accurate. Now government bureaus in many countries study weather conditions very carefully. They use a lot of scientific equipment to help them make accurate forecasts. For instance, they make use of radar, satellites, and computers to gather necessary information about weather.