Part Ⅱ Reading Comprehension(35 minutes) Passage One Questions 21 to 25 are based on the following passage:
Many of the most damaging and life threatening types of weather torrential rains, severe thunderstorms, and tornadoes（龙卷风）– begin quickly, strike suddenly, and disappear rapidly, destroying small regions while leaving neighbouring areas untouched. Such event as a tornado struck the northeastern section of Edmonton, Alberta, in July 1987. Total damages from the tornado exceeded $250 million, the highest ever for any Canadian storm.
Conventional computer models of the atmosphere have limited value in predicting short lived local storms like the Edmonton tornado, because the available weather data are generally not detailed enough to allow computers to study carefully the subtle（微妙的）atmospheric changes that come before these storms. In most nations, for example, weather-balloon observations are taken just once every twelve hours at locations typically separated by hundreds of miles. With such limited data, conventional forecasting models do a much better job predicting general weather conditions over large regions than they do local events.
Until recently, the observation intensive approach needed for accurate, very short-range forecasts, or “Nowcasts,” was not feasible. The cost of equipping and operating many thousands of conventional weather stations was extremely high, and the difficulties involved in rapidly collecting and processing the raw weather data from such a network were hard to overcome. Fortunately, scientific and technological advances have overcome most of these problems. Radar systems, automated weather instruments, and satellites are all capable of making detailed, nearly continuous observation over large regions at a relatively low cost. Communications satellites can transmit data around the world cheaply , and modern computers can quickly compile and analyze this large volume of weather information. Meteorologists（气象学者）and computer scientists now work together to design computer programs and video equipment capable of transforming raw weather data into words, symbols, and vivid graphic displays that forecasters can interpret easily and quickly. As meteorologists have begun using these new technologies in weather forecasting offices, Nowcasting is becoming a reality.
21.The word “exceeded” in paragraph 1 most probably means ____. A) added up to B) were more than C) were about D) were less than
22.Conventional computer models of the atmosphere fails to predict such a short-lived tornado because____. A) the computer is not used to forecast specific local events B) the computers are not advanced enough to predict it C) the weather data people collect are often wrong D) weather conditions in some small regions are not available
23.According to the passage, the word “Nowcast” (paragraph 3) means ____. A) a way of collecting raw weather data B) a forecast which can predict the weather conditions in the small area in an accurate way C) a network to collect instant weather data D) a more advanced system of weather observation
24.According to the passage, ____ is the key factor to making “Nowcasts” a reality.A) scientific and technological advances such as radar, or satellites B) computer scientist C) meteorologists D) advanced computer programs
25.According to the author, the passage mainly deals with ____. A) a tornado in Edmonton, Alberta B) what’s a “Nowcast” C) the disadvantage of conventional computer models of the weather forecast D) a breakthrough in weather forecast
local events.
, and modern computers can quickly compile and analyze this large volume of weather information. Meteorologists（气象学者）and computer scientists now work together to design computer programs and video equipment capable of transforming raw weather data into words, symbols, and vivid graphic displays that forecasters can interpret easily and quickly. As meteorologists have begun using these new technologies in weather forecasting offices, Nowcasting is becoming a reality.
