Wind is the movement of air from an area of high pressure to an area of low pressure. In fact, wind exists because the sun unequally heats the surface of the Earth. As hot air rises, cooler air moves in to fill the gap. As long as the sun shines, the wind will blow. And as long as the wind blows, people will manage it to power their lives.
Ancient sailors used sails to capture the wind and explore the world. Farmers once used windmills to grind their grains and pump water. Today, more and more people are using wind turbines to make electricity from the breeze. Over the past decade, wind turbine use has increased at more than 25 percent a year. Still, it only provides a small part of the world's energy.
Most wind energy comes from turbines that can be as tall as a 20-story building and have three 200-foot-long (60-meter-long) blades. These devices look like giant airplane propellers(螺桨)on a stick. The wind spins the blades, which turn a shaft connected to a generator.
The biggest wind turbines generate enough electricity to supply about 600 U.S. homes. Wind farms have tens and sometimes hundreds of these turbines lined up together in particularly windy spots, like along a ridge. Smaller turbines set up in a backyard can produce enough electricity for a single home or small business.
Wind is a clean source of renewable energy that produces no air or water pollution. And since the wind is free, operational costs are nearly zero once a turbine is erected. Mass production and technology advances are making turbines cheaper, and many governments decrease tax to encourage wind-energy development.
Some people think wind turbines are ugly and complain about the noise the machines make. The slowly rotating blades(螺旋风片) can also kill birds and bats, but not nearly as many as cars, power lines, and high-rise buildings do. The wind is also changeable: If it's not blowing, there's no electricity generated.
Nevertheless, the wind energy industry is increasing sharply. Globally, generation more than quadrupled(四倍) between 2000 and 2006. At the end of last year, global capacity was more than 70,000 megawatts. In the energy-hungry United States, a single megawatt is enough electricity to power about 250 homes. Germany has the most installed wind energy capacity, followed by Spain, the United States, India, and Denmark. Development is also fast growing in France and China.
Industry experts predict that if this pace of growth continues, by 2050 the answer to one third of the world's electricity needs will be found blowing in the wind
63. According to the passage, which of the following statements is true?
A. The rotating blades can kill as many birds as high-rise buildings do
B. Single families are not encouraged to build turbines.
C. The USA produces more wind power than any other country in the world.
D. The noise the turbines make may discourage people from building them.
64. The underlined word “generator” in the third paragraph probably means_______.
A. 电动机                       B. 发电机                          C. 机翼                               D. 飞机引擎
65. If the USA wants to build wind turbines in an area with 30,000 homes, how many
should they build at least?
A. 50.                                    B. 150.                                 C. 250.                                 D. 200.
66. All the following are the advantages of wind energy EXCEPT that_________.
A. it is environmentally friendly                                   B. it is free to build and operate
C. the government supports it                                              D. the energy is clean and renewable