『新东方在线托福听力』为托福考生准备了ETS托福TPO/Official 48 Passage 3阅读练习，TPO/Official 48 Passage 3原文答案解析，TPO/Official 48 Passage 3阅读原文练习音频翻译。

托福TPO/Official 48 Passage 3阅读原文题目答案及解析-新东方托福官方网校手机版

众所周知，一百多年来，城市通常比周围的农村地区温暖。

For more than a hundred years, it has been known that cities are generally warmer than surrounding rural areas.

这个被称为城市热岛的城市暖区会影响空气污染的浓度。

This region of city warmth, known as the urban heat island, can influence the concentration of air pollution.

但是，在查看其影响之前，让我们先了解一下热岛的实际形成方式。

However, before we look at its influence, let’s see how the heat island actually forms.

城市热岛归因于工业和城市发展。

The urban heat island is due to industrial and urban development.

在农村地区，大部分传入的太阳能用于蒸发植被和土壤中的水。

In rural areas, a large part of the incoming solar energy is used in evaporating water from vegetation and soil.

在植被和裸露土壤较少的城市中，大部分太阳能被城市建筑和沥青吸收。

In cities, where less vegetation and exposed soil exist, the majority of the Sun’s energy is absorbed by urban structures and asphalt.

因此，在温暖的白天，城市中较少的蒸发冷却使地表温度比农村地区上升得更高。

Hence, during warm daylight hours, less evaporative cooling in cities allows surface temperatures to rise higher than in rural areas.

The cause of the urban heat island is quite involved.

根据位置，一年中的时间和一天中的时间，任何或者所有下列城市和周围环境之间的差异可能都是重要的：反照率（表面的反射率），表面粗糙度，热量散发，湿气散发和影响净辐射和云滴生成的粒子排放。

Depending on the location, time of year, and time of day, any or all of the following differences between cities and their surroundings can be important: albedo (reflectivity of the surface), surface roughness, emissions of heat, emissions of moisture, and emissions of particles that affect net radiation and the growth of cloud droplets.

到了晚上，太阳能（大量热量储存在城市建筑物和道路中）慢慢释放到城市空气中。

At night, the solar energy (stored as vast quantities of heat in city buildings and roads) is slowly released into the city air.

车辆和工厂以及工业和家庭供暖和制冷设备在夜晚（白天）会散发更多的城市热量。

Additional city heat is given off at night (and during the day) by vehicles and factories, as well as by industrial and domestic heating and cooling units.

高大垂直的城墙阻碍了热能的释放，这些城墙不会像周围相对平坦的乡村表面那样容易释放红外线。

The release of heat energy is retarded by the tall vertical city walls that do not allow infrared radiation to escape as readily as does the relatively level surface of the surrounding countryside.

热量的缓慢释放往往会使夜间城市的温度高于较快冷却的农村地区。

The slow release of heat tends to keep nighttime city temperatures higher than those of the faster-cooling rural areas.

总体而言，热岛在以下情况中是最强的：(1)在没有补偿阳光的晚上；(2)在冬季，当夜晚更长，城市产生更多的热量；(3) 当该地区以高压空气为主时，气压（大气压力）是指给定地区上空的空气质量所施加的压力，该地区风力小，天空晴朗，空气不那么潮湿。

Overall, the heat island is strongest (1) at night when compensating sunlight is absent; (2) during the winter, when nights are longer and there is more heat generated in the city; and (3) when the region is dominated by a high-pressure air pressure (atmospheric pressure) is the pressure exerted by the mass of air above a given place area with light winds, clear skies, and less humid air.

随着时间的推移，越来越多的城市热岛影响气候温度记录，在城市的气候记录中产生人为变暖。

Over time, increasing urban heat islands affect climatological temperature records, producing artificial warming in climatic records taken in cities.

因此，在解释过去一个世纪的气候变化时必须考虑到这种变暖。

This warming, therefore, must be accounted for in interpreting climate change over the past century.

不断向环境中排放污染物可能会影响城市的气候。

The constant outpouring of pollutants into the environment may influence the climate of the city.

某些粒子反射太阳辐射，从而减少到达表面的太阳光。

Certain particles reflect solar radiation, thereby reducing the sunlight that reaches the surface.

有些粒子起到核的作用，在其上形成水和冰。

Some particles serve as nuclei upon which water and ice form.

当相对湿度低至70％时，水蒸气会凝结在这些粒子上，形成霾，大大降低了可见度。

Water vapor condenses onto these particles when the relative humidity is as low as 70 percent, forming haze that greatly reduces visibility.

此外，增加的核（水和冰附着的核）增加了城市出现雾的频率。

Moreover, the added nuclei increase the frequency of city fog.

研究表明，城市中的降水量可能比周围的乡村要多。这种现象的部分原因可能是由于大型建筑物导致地面空气流动减慢并逐渐汇聚，导致城市地形粗糙程度增加。

Studies suggest that precipitation may be greater in cities than in the surrounding countryside; this phenomenon may be due in part to the increased roughness of city terrain, brought on by large structures that cause surface air to slow and gradually converge.

然后，城市上空的空气堆积起来，然后慢慢上升，就像挤牙膏管时的牙膏一样。

This piling up of air over the city then slowly rises, much like toothpaste does when its tube is squeezed.

同时，城市热量使地表空气变暖，使其变得更加不稳定，从而加剧了上升的空气运动，上升的空气运动反过来又有助于形成云和雷暴。

At the same time, city heat warms the surface air, making it more unstable, which enhances rising air motions, which, in turn, aids in forming clouds and thunderstorms.

这个过程有助于解释为什么两者在城市中都更加频繁。

This process helps explain why both tend to be more frequent over cities.

在晴朗的寂静夜晚，当热岛出现时，城市上空就会形成一个小的热低压区。

On clear still nights when the heat island is pronounced, a small thermal low-pressure area forms over the city.

有时，一阵微风（称为乡村风）从乡村吹向城市。

Sometimes a light breeze—called a country breeze—blows from the countryside into the city.

如果郊区有主要的工业区，污染物将被带入城镇中心，并在此集中。

If there are major industrial areas along the outskirts, pollutants are carried into the heart of town, where they tend to concentrate.

如果污染物的垂直混合和扩散受到抑制，这种情况尤其有可能发生。

Such an event is especially probable if vertical mixing and dispersion of pollutants are inhibited.

来自城市地区的污染物甚至可能影响来自它们的顺风向天气。

Pollutants from urban areas may even affect the weather downwind from them.

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

Paragraph 2 mentions all of the following as varying the importance of albedo and other factors EXCEPT

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

According to paragraph 4, how do pollutants reduce the distance it is possible to see?

Select the TWO answer choices that describe ways mentioned in paragraphs 2 and 3 in which solar energy affects urban and rural areas. To receive credit, you must select TWO answers.

Paragraph 3 supports which of the following claims about the interpretation of temperature records?

All of the following are mentioned in paragraph 3 as contributing to an increase in the amount of heat within a city EXCEPT

Which of the sentences below best expresses the essential information in the highlighted sentence in the passage? Incorrect choices change the meaning in important ways or leave out essential information.

Why does the author mention “toothpaste” being squeezed from a tube?

The word “both” in the passage refers to

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

According to paragraph 6, the highest concentration of pollutants is likely to be found

Look at the four squares  that indicate where the following sentence could be added to the passage. The resulting difference in atmospheric pressure between the city and the countryside can cause air to shift.  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.

Climate and Urban Development For more than a hundred years, it has been known that cities are generally warmer than surrounding rural areas. This region of city warmth, known as the urban heat island, can influence the concentration of air pollution. However, before we look at its influence, let’s see how the heat island actually forms. The urban heat island is due to industrial and urban development. In rural areas, a large part of the incoming solar energy is used in evaporating water from vegetation and soil. In cities, where less vegetation and exposed soil exist, the majority of the Sun’s energy is absorbed by urban structures and asphalt. Hence, during warm daylight hours, less evaporative cooling in cities allows surface temperatures to rise higher than in rural areas. The cause of the urban heat island is quite involved. Depending on the location, time of year, and time of day, any or all of the following differences between cities and their surroundings can be important: albedo (reflectivity of the surface), surface roughness, emissions of heat, emissions of moisture, and emissions of particles that affect net radiation and the growth of cloud droplets. At night, the solar energy (stored as vast quantities of heat in city buildings and roads) is slowly released into the city air. Additional city heat is given off at night (and during the day) by vehicles and factories, as well as by industrial and domestic heating and cooling units. The release of heat energy is retarded by the tall vertical city walls that do not allow infrared radiation to escape as readily as does the relatively level surface of the surrounding countryside. The slow release of heat tends to keep nighttime city temperatures higher than those of the faster-cooling rural areas. Overall, the heat island is strongest (1) at night when compensating sunlight is absent; (2) during the winter, when nights are longer and there is more heat generated in the city; and (3) when the region is dominated by a high-pressure air pressure (atmospheric pressure) is the pressure exerted by the mass of air above a given place area with light winds, clear skies, and less humid air. Over time, increasing urban heat islands affect climatological temperature records, producing artificial warming in climatic records taken in cities. This warming, therefore, must be accounted for in interpreting climate change over the past century. The constant outpouring of pollutants into the environment may influence the climate of the city. Certain particles reflect solar radiation, thereby reducing the sunlight that reaches the surface. Some particles serve as nuclei upon which water and ice form. Water vapor condenses onto these particles when the relative humidity is as low as 70 percent, forming haze that greatly reduces visibility. Moreover, the added nuclei increase the frequency of city fog. Studies suggest that precipitation may be greater in cities than in the surrounding countryside; this phenomenon may be due in part to the increased roughness of city terrain, brought on by large structures that cause surface air to slow and gradually converge. This piling up of air over the city then slowly rises, much like toothpaste does when its tube is squeezed. At the same time, city heat warms the surface air, making it more unstable, which enhances rising air motions, which, in turn, aids in forming clouds and thunderstorms. This process helps explain why both tend to be more frequent over cities. On clear still nights when the heat island is pronounced, a small thermal low-pressure area forms over the city.  Sometimes a light breeze—called a country breeze—blows from the countryside into the city.  If there are major industrial areas along the outskirts, pollutants are carried into the heart of town, where they tend to concentrate.  Such an event is especially probable if vertical mixing and dispersion of pollutants are inhibited.  Pollutants from urban areas may even affect the weather downwind from them.