单选题 In the late 1960's, many people in North America turned their attention to environmental problems, and new steel-and-glass skyscrapers were widely criticized. Ecologists pointing {{U}} {{U}} 1 {{/U}} {{/U}}that a cluster of tall buildings in a city often overburdens public transportation and parking lot{{U}} {{U}} 2 {{/U}} {{/U}}.
Skyscrapers are also enormous {{U}} {{U}} 3 {{/U}} {{/U}}, and wasters, of electric power. In one recent year, the addition {{U}} {{U}} 4 {{/U}} {{/U}}17 million square feet of skyscraper office space in New York City raised the {{U}} {{U}} 5 {{/U}} {{/U}}daily demand for electricity by 120,000 kilowatts-- enough to {{U}} {{U}} 6 {{/U}} {{/U}}the entire city of Albany for a day. Glass-wailed skyscraper can be especially {{U}} {{U}} 7 {{/U}} {{/U}}. The heat loss (or gain) through a wall of half-inch plate glass is more than ten times{{U}} {{U}} 8 {{/U}} {{/U}}through a typical masonry wall filled with insulation board. To lessen the strain {{U}} {{U}} 9 {{/U}} {{/U}}heating and air-conditioning equipment, {{U}} {{U}} 10 {{/U}} {{/U}}of skyscrapers have begun to use double-glazed panels of glass, and reflective glasses {{U}} {{U}} 11 {{/U}} {{/U}}with silver or gold mirror films that reduce {{U}} {{U}} 12 {{/U}} {{/U}}as well as heat gain. However, {{U}} {{U}} 13 {{/U}} {{/U}}skyscrapers raise the temperature of the surrounding air and {{U}} {{U}} 14 {{/U}} {{/U}}neighboring buildings. Skyscrapers put severe pressure on a city's sanitation {{U}} {{U}} 15 {{/U}} {{/U}}, too. If fully occupied, the two World Trade Center towers in New York City would alone generate 2.25 million gallons of raw sewage each year--as {{U}} {{U}} 16 {{/U}} {{/U}}as a city the size of Stamford, Connecticut, which has a {{U}} {{U}} 17 {{/U}} {{/U}}of more than 109,000. Skyscrapers also {{U}} {{U}} 18 {{/U}} {{/U}}with television reception, block bird flyways, and obstruct air traffic.
Still, people {{U}} {{U}} 19 {{/U}} {{/U}}to build skyscrapers for all the reasons that they have always built them--personal ambition and the {{U}} {{U}} 20 {{/U}} {{/U}}of owners to have the largest possible amount of rentable space.

【正确答案】 D

【答案解析】本题测试词义搭配。thrifty意为“节俭的，节约的”；economic意为“经济的，节省的”；prosperous意为“繁荣的，繁盛的”；wasteful意为“浪费的，不经济的”。前面的句子说“Skyscrapers are also enormous consumers and wasters，of electric power”，而本句话讲的是Glass-walled skyscraper是否节约能源，所以应选D。