In the late 1960s, many people in North America turned their attention to environmental problems, and new steel-and-glass skyscrapers were widely criticized. Ecologists pointed out that a cluster of tall buildings in a city often overburdens public transportation and parking lot capacities. Skyscrapers are also lavish consumers, and wasters, of electric power. In one recent year, the addition of 17 million square feet of skyscraper office space in New York City raised the peak daily demand for electricity by 120, 000 kilowatts -- enough to supply the entire city of Albany, New York, for a day. Glass-walled skyscrapers can be especially wasteful. The heat loss through a wall of half-inch plate glass is more than ten times that through a typical masonry wall filled with insulation board. To lessen the strain on heating and air-conditioning equipment, builders of skyscrapers have begun to use double-glazed panels of glass, and reflective glasses coated with silver or gold mirror films that reduce glare as well as heat gain. However, mirror-walled skyscrapers raise the temperature of the surrounding air and affect neighboring buildings. Skyscrapers put a severe strain on a citys sanitation facilities, 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 much as a city the size of Stanford, Connecticut, which has a population of more than 109, 000.
2016春鲁教版英语六下Unit 5《How do you get to school》(Section A)word教案
2016春鲁教版英语六下Unit 5《How do you get to school》word单元备课
2016春鲁教版英语六下Unit 7《Why do you like pandas》(第二课时)word教学设计
2016春鲁教版英语六下Unit 5《How do you get to school》(Section A)word学案
2016春鲁教版英语六下Unit 5《How do you get to school》(第一课时)word教学设计
2016春鲁教版英语六下Unit 8《I’m watching TV》(第五课时)word教学设计
2016春鲁教版英语六下Unit 10《Is there a post office near here》(第五课时)word教学设计
2016春鲁教版英语六下Unit 10《Is there a post office near here》(单元备课)word教学设计
2016春鲁教版英语六下Unit 5《How do you get to school》(第五课时)word教学设计
2016春鲁教版英语六下Unit 8《I’m watching TV》(第二课时)word教学设计
2016春鲁教版英语六下Unit 8《I’m watching TV》word单元备课
2016春鲁教版英语六下Unit 10《Is there a post office near here》(Section A)word学案
2016春鲁教版英语六下Unit 5《How do you get to school》(Section A)word学案1
2016春鲁教版英语六下Unit 1《When is your birthday》word单元备课
2016春鲁教版英语六下Unit 5《How do you get to school》(Section B)word学案2
2016春鲁教版英语六下Unit 5《How do you get to school》(第六课时)word教学设计
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2016春鲁教版英语六下Unit 1《When is your birthday》(第三课时)word教学设计
2016春鲁教版英语六下Unit 5《How do you get to school》(Section B)word教案2
2016春鲁教版英语六下Unit 5《How do you get to school》(Section B)word学案1
2016春鲁教版英语六下Unit 9《It’s raining》(第三课时)word教学设计
2016春鲁教版英语六下Unit 5《How do you get to school》(第四课时)word教学设计
2016春鲁教版英语六下Unit 9《It’s raining》(第一课时)word教学设计
2016春鲁教版英语六下Unit 7《Why do you like pandas》(第六课时)word教学设计
2016春鲁教版英语六下Unit 10《Is there a post office near here》(第四课时)word教学设计
2016春鲁教版英语六下Unit 10《Is there a post office near here》(第二课时)word教学设计
2016春鲁教版英语六下Unit 5《How do you get to school》(Section B)word教案1
2016春鲁教版英语六下Unit 8《I’m watching TV》(第六课时)word教学设计
2016春鲁教版英语六下Unit 10《Is there a post office near here》(第一课时)word教学设计
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