托福综合写作阅读文章.doc

Passage one Humans have used the windmill to harness wind power for thousands of years. However, it was not until the 19th century that windmills possessed the features that made them efficient in the same way as modern wind turbine blades. The windmill was refined when its heavy, inefficient wooden blades were replaced with lighter, faster steel blades around 1870. Over the next century, more than six million small windmills were built in the western US, where they pumped ground water for livestock and provided the domestic water supply for families living on remote ranches. The first large windmill to produce electricity was a multi-blade design with a 12-kilowatt capability, built in 1888. Today, wind power is a promising, clean, safe, and environmentally friendly energy resource that can serve as an alternative to electricity generated by fossil fuels such as coal, oil, and natural gas. In 1999, wind-generated electricity exceeded 10,000 megawatts globally, which amounts to approximately 16 million kilowatt-hours of electricity. This is more than enough to serve five medium-sized cities with a population of 350,000 each. Wind-generated electricity is projected to be one of the developing world’s most important sources of energy, and it also has potential for industrialized nations. Wind power could provide 20 percent of the electricity in the US, with turbines installed on less than one percent of the nation’s land area. Within that area, less than 5 percent of the land would be occupied by wind equipment; the remaining 95 percent could continue to be used for farming or ranching. Passage two Professors are normally found in university classrooms, offices, and libraries doing research and lecturing to their students. More and more, however, they also appear as guests on television news programs, giving expert commentary on the latest events in the world. These television appearances are of great benefit to the professors themselves as well as to their