完形填空。 In some areas of the world the weather is very 1_____ and this fact plays an important part in the daily lives of the people. 2_____ they are farmers, fishermen, or sailors, for instance, they 3_____ know about these changes ahead of time. Space scientists and airplane pilots 4_____ need weather 5_____. 6_____ earliest time, men have 7_____ the sky, the wind, and the atmosphere, as well as a variety of other weather signs, in order to make weather 8_____. But often their weather predictions have not been accurate (准确的). Now there are government bureaus (局处) in many places that 9_____ weather conditions very carefully. They use a lot of scientific 10_____ to help them make their forecasts (预报). For instance, they have instruments to 11_____ speed and direction of the wind. Thus they can predict the 12_____ of a storm. They have special balloons, ships, and airplanes to help them 13_____ their accuracy, and they make use of radar, satellites and computers to gather 14____ information. Today when a 15_____ takes off from an airport, he 16_____ know what kind of weather to expect when he reaches his destination (目的地). If there is 17_____ rain or snow in the mountains, a weather bureau can predict the day and 18_____ the hour that a river may overflow (使涨满) its banks many miles away. When a storm is moving in a certain 19_____, the people in that area can learn of it ahead of time and 20_____ it. (     )1.A.fine (     )2.A.Because (     )3.A.can (     )4.A.generally (     )5.A.information (     )6.A.From (     )7.A.noticed (     )8.A.study (     )9.A.research (     )10.A.ways (     )11.A.measure (     )12.A.time (     )13.A.study (     )14.A.necessary (     )15.A.pilot (     )16.A.should (     )17.A.light (     )18.A.even (     )19.A.path (     )20.A.leave B.terrible B.Though B.may B.especially B.fact B.By B.observed B.result B.study B.assistants B.make B.direction B.predict B.impossible B.plane B.can B.slight B.also B.direction B.change C.changeable C.If C.will C.usually C.advice C.Since C.saw C.information C.learn C.instruments C.find C.speed C.increase C.foreign C.person C.must C.large C.besides C.strength C.prepare D.changeless D.When D.need to D.seldom D.result D.After D.discovered D.predictions D.watch D.equipments D.discover D.path D.know D.priceless D.space D.might D.heavy D.including D.speed D.prepare for