2.3. Astronomy & Environmental Science

　　2.3.1 城市扩张 CITY SPRWAL

　　第一段：以前对于城市扩张的研究都是依据推测，最近发明一种方法，可以通过卫星图片检测。

　　第二段：为了取得footing，讲了三种因素对城市扩张的影响。他们是CLIMATE,HILLS,undergroundWATER。这三种都是有影响的。他们首先发现climate是一个原因，in mild climate, people tend to spread out. 还发现hill和mountain也是原因，hill是引起人们在hilly地方建造的成本，而mountain则是barrier，帮助compact city(有道题目说hill和mountain起direct 作用，我觉得是错的);还有地下水也有帮助，easy access to groundwater may help. (有题)

　　第三段：讲了道路系统对城市没有evidence证明影响。虽然以前一直认为有。

　　第四段：讲了城市行政划分(大都市区的城市municipalities数量，也就是法律约束区别)对城市扩张没有影响。虽然以前一直认为有。但是解释说可能是由于人们倾向于住在城市边缘正好外面的地方，这样可以不受城市里严格法律的约束;

　　第五段：总结，然后他们发现有些common complaints是正确的:scattered导致城市基础建设成本增加。作者同意这个，提到获得更多补助的城市的发展更加scattered,然后提到说由于城市的建设需要纳税人的钱，所以纳税人更倾向于不需要那么多基础设施建设的发展模式。小组的目标就是帮人们建立概念

　　Q1 说第二段和第三四段的关系，我选的是二是讲有什么影响了，三是纠正一些以前觉得有影响但实际上没有的。

　　【这里开始是怀疑被删减的部分，根据GG，第一段只提了新研究和卫星】

　　A View Of Urban Sprawl From Outer Space Recent urban development in Los Angeles is less scattered than recent development in Boston. Miami is America&aposs most compact big city and Pittsburgh is most sprawling. Changing the number or size of municipal governments in a metro area has no impact on whether or not urban development is scattered, but controlling access to groundwater does.

　　【控制地下水has impact on是否城市发展呈分散化】

　　These are among the startling findings from a University of Toronto-based team of researchers who used satellite data and aerial photography to create a grid of 8.7 billion data cells tracking the evolution of land use in the continental United States.

　　Matthew Turner and Diego Puga of the University of Toronto, Marcy Burchfield of the Neptis Foundation, a Toronto-based organization focused on urban and regional research, and Henry Overman of the London School of Economics present their findings in the May issue of The Quarterly Journal of Economics, in a paper entitled Causes of Sprawl: A Portrait(标本，模型) from Space. Heavily illustrated with Geographic Information System images, the paper challenges conventional wisdom about urban sprawl and presents a vivid and detailed picture of land consumption in America&aposs cities.

　　【就是说新研究出现】

　　Though urban sprawl is widely regarded as an important environmental and social problem, according to the authors, much of the debate over sprawl is based on speculation推测. The data to conduct detailed and systematic measurement of how and where land is converted to urban use has, until now, simply not been available. Despite widespread interest in the topic, "we know next to nothing (差不多没有)about the extent to which development is scattered or compact, and how this varies across space," they write. 【以前研究的局限：based on speculation】 没有好的measurement。

　　The authors merged high-altitude photos from 1976 with satellite images from 1992 (the most recent available) to create a grid of 8.7 billion 30-metre by 30-metre cells that tracks land use changes nationwide. "The data set we&aposve constructed is unprecedented(空前的) in that we have coverage of the whole continental United States with a very high degree of accuracy for two time periods. That&aposs never been done bore," says Turner.【新研究的优势：覆盖面广：有两个时期的精确图，精确性accuracy】

　　The new high-resolution data allow the authors to observe the amount of open space in the neighborhood of every house in every U.S. city. Since development is more scattered when there is more open space around a house, the authors measured urban sprawl by calculating the average amount of open space in the neighborhood of a house in each city.【measure urban sprawl 的具体方法：计算各个城市的房子附近的空地的平均大小】

　　They found that more recent residential development is not any more(不再)

　　scattered than development was in 1976. 42 percent of land in the square kilometre surrounding the average residential development in 1976 was open space, compared with 43 percent in 1992. (空地增多，也就是城市化的土地变少了，是这个意思不?)”While a substantial amount of scattered residential development was built between 1976 and 1992, overall residential development did not become any more biased toward such sprawling areas."【结论一：scatter现象不再明显了】

　　The authors are quick to point out that any one household would have seen much change in the study period, but that "if we zoom out and look at the city from a distance, we see little change, at least in terms of the proportions of sprawling and compact development: the new city is just like an enlarged version of the old city."【结论二：虽然household 的变化大，但实际city的sprawling并不明显。】

　　Overall, Boston is less scattered than Atlanta, however recent development in Boston has been less compact than recent development in Atlanta. Miami, San Francisco and Los Angeles were the most compact major cities, while Pittsburgh and Atlanta were the most scattered.

　　【下面开始才是重点原文，上面估计删减改写了，重点不多。】

　　The authors also investigated why some cities are more sprawling than others. They found that a city&aposs climate, topography and access to groundwater account for 25 percent of the nationwide variation. When the climate is temperate, people spread out to have more space to enjoy the weather.【研究城市之间sprawling的不同：1，适度气候导致人们spread out】

　　Hilly places see more scattered development as people avoid the costs of building on hillsides — but mountains act as a barrier and lead to more compact development. Places with easy access to groundwater see more scattered development, since people can supply remote houses with water by drilling inexpensive wells rather than paying for water lines. 【研究城市之间sprawling的不同：2，avoid cost of building on hill,hill上面修房子太贵，类似HK太平山，Mountain像栅栏让城市compact，地下水很好很便宜导致scattered】

　　加亮部分有题：估计是推理题，问 mountain对scatter现象的作用有什么不同.这里把握住作者态度即可：hillside会导致scatter，mountain却反而more compact. "The presence of aquifers(蓄水层) is particularly important," says Turner, "and that seems to me to have policy implications. It looks as if controlling access to groundwater is an important way to control whether development spreads or not."【照应文章第一段观点：控制地下水源决定了城市扩张程度】

　　Roads, on the other hand, have no impact on the extent to which development is scattered, despite commonly held belis to the contrary. "We looked at a lot of measures of road density — miles of road per area, average distance to a road, distance to an interstate exit — and we could find no relation between those measures and the scatteredness of development," Turner says. 【道路系统与scattered没有关系】

　　The number of municipalities in a metropolitan area also does not affect development patterns. "You hear about fragmentation of jurisdictions being an important determinant of development patterns and we could find no evidence for that," says Turner. However, the team also found that development near cities is less scattered if it occurs in a municipality than if it occurs in an unincorporated area of a county. This suggests that people may be moving out to just beyond municipal boundaries in order to avoid more stringent municipal regulations.【municipalities行政区域划分也没有关系，但是有个现象：边缘比内部scattered】

　　【猜想1】：这里可以考municipalities影响cities to be less scattered than unincorporated area的原因：avoid more stringent regulations. 人都跑出去了，所以外面更乱

　　One of the common complaints about urban sprawl is that as development spreads, municipal services such as roads, sewers, police and fire protection are more expensive. The authors suggest that this concern is well founded. Development in municipalities that receive larger subsidies from higher levels of government is, on average, more scattered. Says Puga, "This suggests that as local taxpayers are held accountable(=responsible) for infrastructure costs, they respond by insisting on patterns of development that require less infrastructure spending."

　　"People have been eager to rush to policy prescriptions without a very good understanding of the underlying phenomena," says Turner. "We wanted to try to put the policy discussion on sounder footing."【总结】

12月GMAT阅读新题最终版——Natural Science Division(4)12月GMAT阅读新题最终版——Natural Science Division(4)12月GMAT阅读新题最终版——Natural Science Division(4)

　　2.3. Astronomy & Environmental Science

　　2.3.1 城市扩张 CITY SPRWAL

　　第一段：以前对于城市扩张的研究都是依据推测，最近发明一种方法，可以通过卫星图片检测。

　　第二段：为了取得footing，讲了三种因素对城市扩张的影响。他们是CLIMATE,HILLS,undergroundWATER。这三种都是有影响的。他们首先发现climate是一个原因，in mild climate, people tend to spread out. 还发现hill和mountain也是原因，hill是引起人们在hilly地方建造的成本，而mountain则是barrier，帮助compact city(有道题目说hill和mountain起direct 作用，我觉得是错的);还有地下水也有帮助，easy access to groundwater may help. (有题)

　　第三段：讲了道路系统对城市没有evidence证明影响。虽然以前一直认为有。

　　第四段：讲了城市行政划分(大都市区的城市municipalities数量，也就是法律约束区别)对城市扩张没有影响。虽然以前一直认为有。但是解释说可能是由于人们倾向于住在城市边缘正好外面的地方，这样可以不受城市里严格法律的约束;

　　第五段：总结，然后他们发现有些common complaints是正确的:scattered导致城市基础建设成本增加。作者同意这个，提到获得更多补助的城市的发展更加scattered,然后提到说由于城市的建设需要纳税人的钱，所以纳税人更倾向于不需要那么多基础设施建设的发展模式。小组的目标就是帮人们建立概念

　　Q1 说第二段和第三四段的关系，我选的是二是讲有什么影响了，三是纠正一些以前觉得有影响但实际上没有的。

　　【这里开始是怀疑被删减的部分，根据GG，第一段只提了新研究和卫星】

　　A View Of Urban Sprawl From Outer Space Recent urban development in Los Angeles is less scattered than recent development in Boston. Miami is America&aposs most compact big city and Pittsburgh is most sprawling. Changing the number or size of municipal governments in a metro area has no impact on whether or not urban development is scattered, but controlling access to groundwater does.

　　【控制地下水has impact on是否城市发展呈分散化】

　　These are among the startling findings from a University of Toronto-based team of researchers who used satellite data and aerial photography to create a grid of 8.7 billion data cells tracking the evolution of land use in the continental United States.

　　Matthew Turner and Diego Puga of the University of Toronto, Marcy Burchfield of the Neptis Foundation, a Toronto-based organization focused on urban and regional research, and Henry Overman of the London School of Economics present their findings in the May issue of The Quarterly Journal of Economics, in a paper entitled Causes of Sprawl: A Portrait(标本，模型) from Space. Heavily illustrated with Geographic Information System images, the paper challenges conventional wisdom about urban sprawl and presents a vivid and detailed picture of land consumption in America&aposs cities.

　　【就是说新研究出现】

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