『新东方在线托福阅读』为托福考生准备了ETS托福TPO/Official 23 Passage 1阅读练习：According to paragraph 3, why do materials in the countryside have a lower heat capacity than materials in cities do?真题题目及答案解析，TPO/Official 23 Passage 1阅读原文范文音频翻译

托福TPO/Official 23 Passage 1阅读原文According to paragraph 3, why do materials in the countryside have a lower heat capacity than materials in cities do?题目答案及解析-新东方托福官方网校手机版

每座城市都是一个巨大的物质和能量处理器，它有自己的新陈代谢机制。

The city is an extraordinary processor of mass and energy and has its own metabolism.

每日城市所摄入的水、食物和不同种类的能量，和所排出的废水、废料、空气污染物、能量、经过某种变化的材料等相匹配。

A daily input of water, food, and energy of various kinds is matched by an output of sewage, solid waste, air pollutants, energy, and materials that have been transformed in some way.

这过程中涉及到的物质数量极其巨大。

这种能量使用的很多方面都影响了城市的大气环境，尤其是热量的产出。

Many aspects of this energy use affect the atmosphere of a city, particularly in the production of heat.

在冬季，城市本身产出的热量能够达到甚至超出太阳提供的热量。

In winter the heat produced by a city can equal or surpass the amount of heat available from the Sun.

我们用来给建筑供暖的热量最终都会转移到周围的空气中，这种能量转移在隔热不好的建筑里发生的最为迅速。

All the heat that warms a building eventually transfers to the surrounding air, a process that is quickest where houses are poorly insulated.

然而一辆车所产生的热量已经足够给一栋普通的房子提供整个冬天的热能；并且如果房子的隔热足够好，一个成年人体温所提供的热量也足够保持房子的温度了。

But an automobile produces enough heat to warm an average house in winter; and if a house were perfectly insulated, one adult could also produce more than enough heat to warm it.

因此，即使没有工业产生的热量，城市地区仍然会比周边的乡村地区更热一些。

Therefore, even without any industrial production of heat, an urban area tends to be warmer than the countryside that surrounds it.

汽车等所燃烧的油料，并不是唯一热量增加的来源。

The burning of fuel, such as by cars, is not the only source of this increased heat.

城市的相对高温还有两个其他的因素。

Two other factors contribute to the higher overall temperature in cities.

第一种因素是，城市建设中所使用的材料通常都有较高的热容，典型的比如水泥和沥青。

The first is the heat capacity of the materials that constitute the city, which is typically dominated by concrete and asphalt.

白天太阳所提供的热量被这些材料吸收，晚间又释放到大气中。

During the day, heat from the Sun can be conducted into these materials and stored—to be released at night.

相比之下，乡村中的建筑材料热容就很低，主要是因为植被阻碍了热量和地面之间的传播。

But in the countryside materials have a significantly lower heat capacity because a vegetative blanket prevents heat from easily flowing into and out of the ground.

第二张因素是，太阳给城市带来的热辐射，通过两种方式被城市拦截了：(1) 通过光在垂直的建筑表面之间一系列的反射，和(2)大多数城市由于污染所产生的，像云一样的漂浮在城市高空的尘埃穹顶。

The second factor is that radiant heat coming into the city from the Sun is trapped in two ways: (1) by a continuing series of reflections among the numerous vertical surfaces that buildings present and (2) by the dust dome, the cloudlike layer of polluted air that most cities produce.

波长较短的太阳光辐射能够轻易穿透这层尘埃，但向外散热的长波辐射则被这些污染气息吸收，并且辐射回城市表面。

Shortwave radiation from the Sun passes through the pollution dome more easily than outgoing longwave radiation does; the latter is absorbed by the gaseous pollutants of the dome and reradiated back to the urban surface.

因此，城市就要比周边的乡村要热。他们共同产生了一种现象：城市热岛效应。

Cities, then, are warmer than the surrounding rural areas, and together they produce a phenomenon known as the urban heat island.

风力不大的条件最有利于热岛的形成，但其实任何条件下都是可以出现的。

Heat islands develop best under particular conditions associated with light winds, but they can form almost any time.

热岛具体的形态取决于一些不同的因素。

The precise configuration of a heat island depends on several factors.

例如，风可以把热岛沿着风向拉长。

For example, the wind can make a heat island stretch in the direction it blows.

一个完全形成的热岛的差异可能是非常明显的。在冬天的时候，繁忙的主干道路边可能比支线道路暖1.7°C。

When a heat island is well developed, variations can be extreme; in winter, busy streets in cities can be 1.7°C warmer than the side streets.

类似地，由于车辆阻塞带来的效应，交通灯附近的区域也会比两个交通灯之间的区域更暖。

Areas near traffic lights can be similarly warmer than the areas between them because of the effect of cars standing in traffic instead of moving.

相邻的城区和乡村环境之间的最大温差，叫做当地的热岛强度。

The maximum differences in temperature between neighboring urban and rural environments is called the heat-island intensity for that region.

一般来说，城市越大，热岛强度越大。

In general, the larger the city, the greater its heat-island intensity.

该强度的实际水平则取决于包括城市布局，人口密度和城市的生产活动等因素。

The actual level of intensity depends on such factors as the physical layout, population density, and productive activities of a metropolis.

大都会地区等这些地表-大气关系，带来了很多该地区独有的气候特征。

The surface-atmosphere relationships inside metropolitan areas produce a number of climatic peculiarities.

例如，城市的特殊地表特征会影响大气的湿度。

For one thing, the presence or absence of moisture is affected by the special qualities of the urban surface.

由于雨水无法渗透大部分的人工建筑，哪怕很轻微的降水也会立刻从屋顶、路面和停车场流走。

With much of the built-up landscape impenetrable by water, even gentle rain runs off almost immediately from rooftops, streets, and parking lots.

因此城市的路面和表层大气通常会在降水之间更为干燥，由于几乎没有水分参与蒸发降温的过程，相对湿度通常都比较低。

Thus, city surfaces, as well as the air above them, tend to be drier between episodes of rain; with little water available for the cooling process of evaporation, relative humidities are usually lower.

另外，由于建筑物会增加周围空气移动时受到的摩擦，城市中的风向也会被改变。

Wind movements are also modified in cities because buildings increase the friction on air flowing around them.

这些摩擦容易把风速减慢，使得空气污染物仍不容易被风扩散和消除。

This friction tends to slow the speed of winds, making them far less efficient at dispersing pollutants.

另外，由于摩天建筑对于气流的影响，城市中的空气乱流也出现得更加频繁。

On the other hand, air turbulence increases because of the effect of skyscrapers on airflow.

部分降水量增加可能是由于热空气从地面上升所引发更剧烈的乱流导致的。

The cause appears to be in part greater turbulence in the urban atmosphere as hot air rises from the built-up surface.

The word “enormous” in the passage is closest in meaning to

The word “surpass” in the passage is closest in meaning to

According to paragraph 2, how soon heat from a warmed house reaches the outside air is greatly affected by

According to paragraph 3, each of the following contributes to making urban areas warmer than the surrounding countryside EXCEPT

According to paragraph 3, why do materials in the countryside have a lower heat capacity than materials in cities do?

The word “configuration” in the passage is closest in meaning to

According to paragraph 4, what can explain the substantial differences in temperature between one area and another within a well-developed heat island?

Paragraph 4 supports the idea that a city's heat-island intensity would increase if

According to paragraph 5, surfaces in the city are generally drier than surfaces in the countryside between periods of rainfall because

The word “modified” in the passage is closest in meaning to

According to paragraph 5, which of the following is a factor responsible for the greater air turbulence in urban environments?

Look at the four squares  that indicate where the following sentence could be added to the passage. Another possibility is for the heat island to be stretched along the course of major rivers, since large waterways typically have a warming effect on the air directly above them.  Where would the sentence best fit? Click on a square  to add the sentence to the passage.

Directions: An introductory sentence for a brief summary of the passage is provided below. Complete the summary by selecting the THREE answer choices that express the most important ideas in the passage. Some sentences do not belong in the summary because they express ideas that are not presented in the passage or are minor ideas in the passage. This question is worth 2 points.

Urban Climates The city is an extraordinary processor of mass and energy and has its own metabolism. A daily input of water, food, and energy of various kinds is matched by an output of sewage, solid waste, air pollutants, energy, and materials that have been transformed in some way. The quantities involved are enormous. Many aspects of this energy use affect the atmosphere of a city, particularly in the production of heat. In winter the heat produced by a city can equal or surpass the amount of heat available from the Sun. All the heat that warms a building eventually transfers to the surrounding air, a process that is quickest where houses are poorly insulated. But an automobile produces enough heat to warm an average house in winter; and if a house were perfectly insulated, one adult could also produce more than enough heat to warm it. Therefore, even without any industrial production of heat, an urban area tends to be warmer than the countryside that surrounds it. The burning of fuel, such as by cars, is not the only source of this increased heat. Two other factors contribute to the higher overall temperature in cities. The first is the heat capacity of the materials that constitute the city, which is typically dominated by concrete and asphalt. During the day, heat from the Sun can be conducted into these materials and stored—to be released at night. But in the countryside materials have a significantly lower heat capacity because a vegetative blanket prevents heat from easily flowing into and out of the ground. The second factor is that radiant heat coming into the city from the Sun is trapped in two ways: (1) by a continuing series of reflections among the numerous vertical surfaces that buildings present and (2) by the dust dome, the cloudlike layer of polluted air that most cities produce. Shortwave radiation from the Sun passes through the pollution dome more easily than outgoing longwave radiation does; the latter is absorbed by the gaseous pollutants of the dome and reradiated back to the urban surface. Cities, then, are warmer than the surrounding rural areas, and together they produce a phenomenon known as the urban heat island. Heat islands develop best under particular conditions associated with light winds, but they can form almost any time.  The precise configuration of a heat island depends on several factors.  For example, the wind can make a heat island stretch in the direction it blows.  When a heat island is well developed, variations can be extreme; in winter, busy streets in cities can be 1.7°C warmer than the side streets.  Areas near traffic lights can be similarly warmer than the areas between them because of the effect of cars standing in traffic instead of moving. The maximum differences in temperature between neighboring urban and rural environments is called the heat-island intensity for that region. In general, the larger the city, the greater its heat-island intensity. The actual level of intensity depends on such factors as the physical layout, population density, and productive activities of a metropolis. The surface-atmosphere relationships inside metropolitan areas produce a number of climatic peculiarities. For one thing, the presence or absence of moisture is affected by the special qualities of the urban surface. With much of the built-up landscape impenetrable by water, even gentle rain runs off almost immediately from rooftops, streets, and parking lots. Thus, city surfaces, as well as the air above them, tend to be drier between episodes of rain; with little water available for the cooling process of evaporation, relative humidities are usually lower. Wind movements are also modified in cities because buildings increase the friction on air flowing around them. This friction tends to slow the speed of winds, making them far less efficient at dispersing pollutants. On the other hand, air turbulence increases because of the effect of skyscrapers on airflow. Rainfall is also increased in cities. The cause appears to be in part greater turbulence in the urban atmosphere as hot air rises from the built-up surface.