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.
外研版英语新编基础训练九年级下册Module 3 Unit 3答案
北师大版六年级下册英语课本Unit 8 Lesson 6部分课后答案
译林版英语新编基础训练九年级下册单元检测Unit 4答案
北师大版六年级下册英语课本Unit 9 Lesson 3部分课后答案
外研版英语新编基础训练九年级下册Module 5 Unit 2答案
外研版英语新编基础训练九年级下册单元检测Module 8答案
外研版英语新编基础训练九年级下册Module 7 Unit 3答案
外研版英语新编基础训练九年级下册单元检测Module 7答案
外研版英语新编基础训练九年级下册Module 5 Unit 3答案
北师大版六年级下册英语课本Unit 7 Lesson 2部分课后答案
外研版英语新编基础训练九年级下册Module 8 Unit 1答案
外研版英语新编基础训练九年级下册单元检测Module 4答案
外研版英语新编基础训练九年级下册Module 2 Unit 3答案
外研版英语新编基础训练九年级下册Module 6 Unit 1答案
北师大版六年级下册英语课本Unit 8 Lesson 4部分课后答案
北师大版六年级下册英语课本Unit 8 Lesson 2部分课后答案
外研版英语新编基础训练九年级下册Module 6 Unit 3答案
外研版英语新编基础训练九年级下册单元检测Module 3答案
译林版英语新编基础训练九年级下册单元检测Unit 3答案
外研版英语新编基础训练九年级下册Module 2 Unit 1答案
外研版英语新编基础训练九年级下册Module 1 Unit 3答案
译林版英语新编基础训练九年级下册综合测试(期末)答案
外研版英语新编基础训练九年级下册综合测试期中答案
外研版英语新编基础训练九年级下册Module 2 Unit 2答案
北师大版六年级下册英语课本Unit 8 Lesson 5部分课后答案
北师大版六年级下册英语课本Unit 9 Lesson 2部分课后答案
外研版英语新编基础训练九年级下册Module 3 Unit 2答案
外研版英语新编基础训练九年级下册单元检测Module 5答案
北师大版六年级下册英语课本Unit 8 Lesson 3部分课后答案
译林版英语新编基础训练九年级下册综合测试(期中)答案
不限 |
英语教案 |
英语课件 |
英语试题 |
不限 |
不限 |
上册 |
下册 |
不限 |