托福TPO48阅读真题Part3原文：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 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 risings 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 heat 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.
托福TPO48阅读真题Part3题目：
Paragraph 2
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.
1. The word “involved” in the passage is closest in meaning to
A. uncertain
B. complicated
C. common
D. clear
2. Paragraph 2 mentions all of the following as varying the importance of albedo and other factors EXCEPT
A. seasons
B. soil depth
C. geographic location
D. the time of day
Paragraph 3
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 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.
3. The word “retarded” in the passage is closest in meaning to
A. disguised
B. added to
C. made possible
D. slowed down
Paragraph 4
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.
4. According to paragraph 4, how do pollutants reduce the distance it is possible to see?
A. They increase the amount of sunlight that reaches the ground.
B. They increase the relative humidity.
C. They form particles that irritate the eye.
D. They serve as nuclei around which water condenses.
Paragraph 2 and Paragraph 3
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 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.
5. 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.
A. Solar energy causes evaporation from vegetation and soil, producing a cooling effect.
B. Solar energy stored as heat is lost quickly when tall city buildings guide hot air up and away from the surface.
C. Solar energy increases the atmospheric pressure over open areas.
D. Solar energy is stored up in buildings and roads and emitted as heat during the night.
6. Paragraph 3 supports which of the following claims about the interpretation of temperature records?
A. The climate may not be warming as much as the increase of temperatures recorded in cities appears to suggest.
B. Records show that the increase in urban heat islands has had a significant warming effect on the global climate.
C. During most of the past century, temperature records have been misinterpreted.
D. Scientists will not be able to account for climate change over the past century until they learn more about the urban heat island.
7. All of the following are mentioned in paragraph 3 as contributing to an increase in the amount of heat within a city EXCEPT
A. home air conditioners
B. cars and trucks
C. streetlights
D. factory buildings
8. 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. (文中未显示阴影部分)
A. Until more studies are done, suggestions about the causes of precipitation in cities will focus on the roughness of terrain rather than on surface air and convergence.
B. Certain phenomena of city landscapes, such as large structures, cause surface air to slow and converge, which brings a change in weather patterns to cities and rural areas.
C. One reason why precipitation may be greater in cities than in the countryside is that large buildings that are found in cities cause surface air to slow and converge.
D. Studies that focus on large structures, which are only partly responsible for the increased roughness of city terrain, are incomplete in their explanation of increased precipitation.
Paragraph 5
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 risings air motions, which, in turn, aids in forming clouds and thunderstorms. This process helps explain why both tend to be more frequent over cities.
9. Why does the author mention “toothpaste” being squeezed from a tube?
A. To compare the movement of toothpaste from a tube to the movement of precipitation from clouds
B. To suggest that the process of cloud formation is a simple, everyday experience
C. To help the reader visualize the process of air movement over a city
D. To contrast the slow rising of air currents with the rapid squeezing of toothpaste
10. The word “both” in the passage refers to
A. piling up and warming of air
B. clouds and thunderstorms
C. warm surface air and rising air motions
D. heat and instability
Paragraph 6
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 heat 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.
11. The word “pronounced” in the passage is closest in meaning to
A. examined
B. relative
C. strongest
D. darkest
12. According to paragraph 6, the highest concentration of pollutants is likely to be found
A. in the center of the city
B. over industrial areas outside the city
C. in rural areas downwind of the city
D. high in the atmosphere during daylight hours
12. Look at the four squares [■] that indicate where the following sentence could be added to the passage.
The resulting difference in atmosphere 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.
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 heat 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.
13. 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.
Drag your answer choices to the spaces where they belong. To remove an answer choice, click on it.
To review the passage, click VIEW TEXT.
Cities are generally warmer than the surrounding countryside, a phenomenon known as the urban heat island.
Answer Choices
A. In the countryside, much solar energy is used in evaporation, but in the city this energy builds up as heat.
B. Increased industrial and urban development has also increased average levels of humidity over the last century.
C. Pollution from cars and factories helps increase the amounts of fog and precipitation that occur in cities.
D. The urban heat island is strongest in the summer, when the days are long and the sunlight is intense.
E. Heat and air are trapped in the irregular spaces between buildings, which creates the atmospheric conditions that result in storms and winds.
F. Country breezes blow pollutants put from the cities into the surrounding countryside.
托福TPO48阅读真题Part3答案：
1-4.BBDD 5.AD 6-10.ACCCB 11-13.CAA 14.ACE