e 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 ing into the city from the Sun is trapped in two ways： by a continuing series of reflections among the numerous vertical surfaces that buildings present and 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 17℃ 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。
Question： Cities create climatic conditions of their own through their physical structure and urban activities。
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Answer Choices
1。 The amount of heat produced in a city will be reduced when cities use the heat from cars to warm houses。
2。 The built up landscape of the city readily bees a heat island； with greater water runoff and special climatic conditions such as low relative humidity and increased air turbulence。
3。 The materials from which cities are built and the effects of pollution domes help make urban areas warmer than rural areas。
4。 Cities tend to be warmer than their surrounding areas； in part because they produce heat by burning fuel for heating； powering vehicles； and industrial production。
5。 In most cities； the heating that results from solar radiation is intensified by carbon dioxide； a gas that is present at very high concentrations in cities’ atmospheres。
6。 During periods without rainfall； the air in cities heats up and causes winds to slow down with the result that pollutants are not dispersed。
阅读题干，可以知道题目要求选出符合“城市自身结构和城市活动会形成其自身的气候条件”这一说法的选项。
观察选项，第一项的意思是“城市产生的热量会受因汽车的使用等因素影响”，而这只是支持“城市活动会影响气候”这一观点的一个细节，没有概括地谈及气候的形成，因此不符合题意；
第二项主要讲的是“城市地貌特征很容易形成热岛”，是对文章最后两段的总结，因此符合题意；
第三项讲的是“城建材料和污染会使城市比农村更温暖”，是文章第三段提到的“两个影响气候的因素”的其中一个，因此符合题意；
第四项表述的是“城市中燃料的使用也会使温度升高”，这与文章第四段的观点相符，因此是正确选项；
第五项讲的是“城市大气中的二氧化碳能使太阳辐射产生的热量变得更多”；和第一个选项一样，这也是一个细节性的陈述；
第六项提到“在没有降雨的时期，城市中的空气会升温，使风速减慢，因此污染物不容易扩散”，这不符合题目的要求，因此可以确定不是正确选项。
图表题则需要考生在备选答案中选出正确的选项填入表格。要做好这道题，考生需要对文章的结构有一个清晰的了解。建立的文章结构大纲要包含重要的细节，以及作者的观点，这样才能有助于选择正确的答案。
三、必备阅读技巧
想在托福阅读考试中获得高分，除了熟悉考试中常见的单词、文章的特点，以及题目类型以外，掌握一些解题必备技巧也是必不可少的。
在实际考试中，我们可以参考以下这些有助于提高阅读成绩的技巧：
1。 在原文中找出处
在选择答案的时候，一定要回到原文中找到根据，否则很容易被干扰选项误导，做出错误的选择。
2。 通过关键词定位
托福阅读考试时间有限，因此要掌握略读的技巧。可以提取题目中的关键词，确定考查点，然后直接回到原文相应的段落定位答案，而其他不重要的信息则可以略过。
3。 通过上下文猜测词义
对于考查某个特定单词意思的问题，如果不认识这个词，那么一定不能放过它前后的句子，可以试着通过上下文推断出它的含义。
4。 熟悉错误答案的出题路数
平时在练习的时候，也要关注错误选项的出题路数。比如可能在选项中换掉那些修饰程度的副词，使选项涉及的范围扩大或缩小等。
Part 3 托福阅读话题词汇
自然科学篇
abundant［？'b？nd？nt］a。 大量的；充足的；丰富的
例句 1。 By now； the most abundant type of groundwater is meteoric water that circulates as part of the water cycle。 到目前为止，种类最丰富的地下水是大气水，它是水文循环的一部分。
2。 The early explorers and settlers said there were once abundant deer in the early 1800s and yet bemoaned the lack of game animal at that time。 早期的探险者和移民表示，这里在19世纪早期曾有大量的鹿，但令他们感到惋惜的是当时没有狩猎动物。
同义 plentiful（a。 大量的；充足的）
派生 abundantly（ad。 大量地；丰富地）
absorption［？b'z？：rp？n］n。 吸收；专心致志
例句 In this area； water absorption of the rock is greatly reduced； thus runoff is increased； resulting in accelerated erosion rates。 在这个地区，岩石的吸水率急剧下降，因此导致水土流失的加剧，造成腐蚀速度的加快。
2。 Due to the plete absorption in the research； he found the answer finally。 由于全心投入研究，他最终找到了答案。
同义 assimilation； reception（n。 吸收）
accumulation［？？kju：mj？'lei？n］n。 积累；堆积物
例句 1。 Ecosystems include the circulation； transformation； and accumulation of energy and matter through the medium of living things and their activities。 生态系统包括以其中的生物及其活动为媒介的能量和物质的循环、转化和积累。
2。 A number of members of the mustard family； spurge family； legume family； and grass family are top hyper accumulators； most of them are found in tropical and subtropical areas where accumulation of high concentrations of metals may provide some protection against plant…eating insects and microbial pathogens。 许多十字花科、大戟科、豆科以及禾本科的植物都是超积累植物；它们中的多数可在热带及亚热带地区生长，在这些地区，高浓度的金属元素积累可以为这些植物提供保障来抵抗那些以植物为食的昆虫和微生物致病体。
同义 amassing； cumulation（n。 积累）
altitude［'？ltitu：d］n。 海拔，高度；［常 pl。］高处
搭配 pressure altitude 压力高度
例句 1。 The trees at high altitudes with deformed shapes show that wind velocity； which increases with altitude； can cause serious hardship for trees。 生长在高海拔地区的畸形树木可以显示风速随着海拔的上升而加强，会给树木生长带来严重影响。
2。 The increase of altitude leads to a sharp decrease in the number of trees。 随着海拔的升高，树木的数量急剧减少。
3。 This plant failed to transport water to the area of high altitudes。 这家工厂无法把水运送到高海拔地区。
同义 height（n。 高度）
aquifer［'？kwif？r］n。 含水土层；蓄水层
搭配 confined aquifer 承压含水层
例句 1。 An aquifer is a kind of underground layer of rock