The city is anextraordinaryprocessor ofmassand energy and has its ownmetabolism. A daily input of water, food, and energy of various kinds is matched by anoutputofsewage,solidwaste,airpollutants, energy, and materials that have been transformed in some way. The quantities involved areenormous. Many aspects of this energy useaffecttheatmosphereof a city, particularly in the production of heat.

In winter the heat produced by a city canequalorsurpasstheamountof heatavailablefrom the Sun. All the heat that warms a buildingeventuallytransfers to the surroundingair, aprocessthat is quickest where houses are poorlyinsulated. But anautomobileproduces enough heat to warm anaveragehouse in winter, and if a house were perfectlyinsulated, one adult could also produce more than enough heat to warm it. Therefore,evenwithout anyindustrialproduction of heat, anurbanarea tends to be warmer than the countryside that surrounds it.

The burning offuel, such as by cars, is not the onlysourceof this increased heat. Two other factorscontributeto the higheroveralltemperaturein cities. The first is the heatcapacityof the materials thatconstitutethe city, which is typically dominated byconcreteand 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 asignificantlylowerheatcapacitybecause avegetativeblanketprevents heat from easily flowing into and out of the ground. Thesecondfactoris thatradiantheat coming into the city from the Sun is trapped in two ways: (1) by a continuingseriesofreflectionamong thenumerousverticalsurfaces that buildings present and (2) by the dustdome, the cloudlikelayerof pollutedairthat most cities produce. Shortwaveradiationfrom the Sun passesthroughthe pollutiondomemore easily than outgoing longwaveradiationdoes; thelatteris absorbed by thegaseouspollutants of thedomeand reradiated back to theurbansurface.

Cities, then, are warmer than the surroundingruralareas, and together they produce aphenomenonknown as theurbanheat island.Heat islands develop best underparticularconditions

associated with light winds, but they can form almost any time.Thepreciseconfigurationof a heat island depends on several factors.For example, the wind can make a heat islandstretchin the direction it blows.When a heat island is well developed,

variations can beextreme; in winter, busy streets in cities can be 1.7℃ 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 trafficinsteadof moving.Themaximumdifferences intemperaturebetween neighboringurbanandruralenvironments is called the heat-island intensity for thatregion.In general, the larger the city, the greater

its heat-island intensity.The actuallevelof intensity depends on such factors as thephysicallayout,populationdensity, andproductiveactivities of ametropolis. Heat islands develop best underparticularconditions

associated with light winds, but they can form almost any time. Thepreciseconfigurationof a heat island depends on several factors. For example, the wind can make a heat islandstretchin the direction it blows. When a heat island is well developed,

variations can beextreme; in winter, busy streets in cities can be 1.7℃ 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 trafficinsteadof moving. Themaximumdifferences intemperaturebetween neighboringurbanandruralenvironments is called the heat-island intensity for thatregion. In general, the larger the city, the greater

its heat-island intensity. The actuallevelof intensity depends on such factors as thephysicallayout,populationdensity, andproductiveactivities of ametropolis.

The surface-atmosphere relationships insidemetropolitanareas produce a number ofclimaticpeculiarities. For one thing, the presence orabsenceofmoistureis affected by thespecialqualities of theurbansurface. With much of the built-uplandscapeimpenetrableby water,evengentlerain runs off almost immediately from rooftops, streets, andparkinglots. Thus, city surfaces, as well as theairabove them,tendto be drier between episodes of rain; with little wateravailablefor the coolingprocessofevaporation,relativehumidities are usuallylower. Wind movements are also modified in cities because buildings increase thefrictiononairflowing around them. Thisfrictiontends to slow the speed of winds, making them far lessefficientat dispersing pollutants. On the other hand,airturbulenceincreases because of the effect of skyscrapers onairflow. Rainfallis also increased in cities. The cause appears to be in part greaterturbulencein theurbanatmosphereas hotairrises from the built-up surface.

Questions:
question_stem: The word “enormous” in the paragraph 1 is closest in meaning to
choices: tag: A
text: growing

tag: B
text: frightening

tag: C
text: very large

tag: D
text: strictly controlled
answer_key: C
explanation: enormous: 巨大的。A 是增长的，B 是令人恐惧的，C 是非常巨大的，D 是严格控制的。所以正确答案是 C 的 very large。

question_stem: The word “surpass” in the paragraph 2 is closest in meaning to
choices: tag: A
text: remain below

tag: B
text: be higher than

tag: C
text: add to

tag: D
text: come close to
answer_key: B
explanation: B surpass: 超过。A 是保持低于, B 选项是比…高，C 是加到，增加，D 是接近，所以正确答案是 be higher than。

question_stem: According to paragraph 2, how soon heat from a warmed house reaches the outside air greatly affected by
choices: tag: A
text: how well the house is heated

tag: B
text: how well the house is insulated

tag: C
text: how many adults live in the house

tag: D
text: how much sunshine the house receives
answer_key: B
explanation: B 以 warmed house 和 outside air 做关键词定位至第二句，说当房间隔热差的时候，热量散失最快，所以散失的快慢应该取决于房屋的隔热状况，所以正确答案是 b，其他答案都没说。

question_stem: According to paragraph 3, each of the following contributes to making urban areas warmer than the surrounding countryside EXCEPT
choices: tag: A
text: the fuel burned by motor vehicles

tag: B
text: the capacity to store heat of the materials used in building a city

tag: C
text: the easy flow of heat into the ground in city areas covered by vegetation

tag: D
text: the repeated reflection of solar radiation back and forth among buildings
answer_key: C
explanation: C except 题，排除法。a 的 motor vehicles 做关键词定位至第一句的 cars，说 fuel 燃烧不是唯一来源，明显是一个来源，所以 a 正确，不选；b 在上一段有说到，所以也正确，不选(我的版本 b 答案和上一题的 b 答案是一样的，我怀疑是搞错了，而且如果只是像题目问的根据第三段，这个答案又不对，但选项 c 也错了，谁能告诉我是肿么回事)；c 的 vegetation 做关键词定位至第五句，但说的是 countryside，没说 urban，所以 c 错，选；d 的 reflection 做关键词定位至两个 ways 的第一个，正确，不选。

question_stem: According to paragraph 3, why do materials in the countryside have a lower heat capacity than materials in cities do?
choices: tag: A
text: In the countryside the Sun is the only important source of heat.

tag: B
text: Construction materials in the city are not as good at keeping buildings warm as they are in the countryside.

tag: C
text: In the countryside the solar heat that flows into the ground flows out again quickly.

tag: D
text: Countryside vegetation prevents heat from being trapped in the ground.
answer_key: D
explanation: D 以 lower heat capacity 做关键词定位至第五句，说农村的 heat capacity 低于城市是因为植被覆盖使得 heat 不那么容易进入或者流出地表，所以正确答案是 d。a 的 only source，b 的 construction materials 都没说，c 说反了，原文说不那么容易。

question_stem: How is paragraph 3 organized?
choices: tag: A
text: It describes two factors that contribute to the increased heat of cities and then provides two causes for the second factor.

tag: B
text: It describes two causes discovered in an early analysis of the increased heat of cities.

tag: C
text: It describes two factors that contribute to the increased heat of cities and two other factors that work against it.

tag: D
text: It describes two well-established causes of the increased heat of cities and other two whose roles are less well understood.
answer_key: A
explanation: A 问整段的，看开头和第二句。首句说机动车不是唯一因素，第二句说还有两个其他的因素，然后后文详细叙述了这两个因素都是什么，并且在描述第二个因素的时候，说了两个原因。所以正确答案是 A。B 的 early analysis，B 的 work against it 和 D 的 less well understood 都没说，而且 A 特别提到了 two causes for the second factor。

question_stem: The word “configuration” in the paragraph 4 is closest in meaning to
choices: tag: A
text: location

tag: B
text: history

tag: C
text: temperature

tag: D
text: shape
answer_key: D
explanation: D configuration: 结构，外形。A 是位置，B 是历史，C 是温度，D 是形状所以 D 的 shape 是正确答案。

question_stem: According to paragraph 4, what can explain the substantial differences in temperature between one area and other within a well-developed heat island?
choices: tag: A
text: The overall size of the heat island that includes the two reasons

tag: B
text: The intensity of the heat island that includes the two areas

tag: C
text: Differences between the two areas in the general level of activity, including traffic

tag: D
text: Differences between the two areas in the insulation materials used in construction
answer_key: C
explanation: C  以 difference 和 well-developed heat island 双关键词定位至第五和第六句，说 well developed 的热岛里的变化是非常大的，在冬天，繁忙街道可以比不繁忙的高17度，后来又说信号灯所在的位置比没有信号灯的位置热，都在说交通，所以 c 是对的，说城市的繁忙情况，包括交通。a 的 size，b 的 intensity 和 d 的 insulation materials 都没说到。

question_stem: Paragraph 4 supports the idea that a city’s heat-island intensity would increase if
choices: tag: A
text: the city went into an economic decline and lost population

tag: B
text: the city’s economy shifted from heavy industry to health care and education

tag: C
text: there was an upward trend in the average age of the city’s residents

tag: D
text: repair work on the streets slowed traffic throughout the city
answer_key: D
explanation: D 以 intensity 做关键词定位至倒数三句，说城市越大 intensity 越强，还取决于 layout，population density 和 productive activity，所以正确答案是 d，而且也可以根据上一题得出这个答案。a 说反了，如果 population 少 intensity 应该下降；b 的 shift 和 c 的 age 都没说。

question_stem: According to paragraph 5, surfaces in the city are generally drier than surfaces in the countryside between periods of rainfall because
choices: tag: A
text: in the city gentle rain is much more common than heavy rain

tag: B
text: high temperatures in the city speed up the process of evaporation

tag: C
text: in the city there are longer periods of dry weather between episodes of rain

tag: D
text: rainwater in the city cannot soak into most surfaces and quickly runs off
answer_key: D
explanation: D 以 rainfall 做关键词定位至第三句，说城市的建筑大多是不透水的，即使是最小的雨也会流走，这是城市地表干燥的原因，所以正确答案是 d。a 的 gentle rain much more common，b 的 speed up 和 c 的 longer periods of dry weather 原文都没说，不选

question_stem: The word “modified” in the paragraph 5 is closest in meaning to
choices: tag: A
text: changed

tag: B
text: blocked

tag: C
text: increased

tag: D
text: weakened
answer_key: A
explanation: A  modify: 改变。A 是改变，B 是阻挡，C 是增加，D 是减弱。正确答案是 A 的 change。

question_stem: According to paragraph 5, which of the following is a factor responsible for the greater air turbulence in urban environments?
choices: tag: A
text: The high speed of the winds travelling above cities

tag: B
text: The greater rainfall totals recorded in cities

tag: C
text: Attempts to reduce urban air pollution

tag: D
text: The effects of tall buildings on airflow
answer_key: D
explanation: D  以 air turbulence 做关键词定位至倒数第三句，说 air turbulence 增加是因为高层建筑影响气流，所以正确答案是 d。a 的 high speed，b 的 rainfall 和 c 的 air pollution 原文都没说，不选