发布时间 : 星期日 文章TPO48 阅读文本答案翻译更新完毕开始阅读
参考译文：确定恐龙的饮食
要确定已经灭绝的恐龙吃什么是一件很困难的事情，但是我们能推测出它们在饮食上的一些偏好。传统上，这些信息来自直接证据，如胃内食物，以及间接证据，如通过在恐龙的特定身体特征和现今存活的动物的饮食习惯之间建立关系来推断恐龙的饮食习惯。
像家养的猫和狗这类动物，嘴前部的牙齿又大又尖，后部的牙齿要小一些但是同样锋利。这些动物中有许多都有着锋利的爪子。牙齿和爪子作为捕食工具的优势非常明显。现在再看牛、马、兔子和老鼠这些动物。它们后部的牙齿比较扁平，功能类似于研磨的石头。不像食肉动物的牙齿是刺进肉里并把肉撕开，这些动物的牙齿会将植物磨成碎块再消化。
头骨的其他部分存在更多线索。狗和猫这类食肉动物的颌关节和牙齿在同一高度上，这种机械上的优势能使上下颌快速闭合，使得上下牙齿咬合严密。对草食动物来说，快速颌闭合并不重要。由于食草动物的扁平牙齿像磨刀石一般，上下颌必须前后左右移动。许多高等草食动物，如牛，颌关节和牙齿的高度并不一致，这样它们就能横向撕裂、切碎和挤压植物。如果我们把这种观察方法应用到灭绝的恐龙身上，我们可以推断出恐龙的饮食偏好（如肉食还是草食），虽然我们无法确定准确的食物。鸭嘴龙便是一个颌关节比牙齿低的例子，这种高度不一致可能会帮助它们把坚韧的纤维植物磨碎。
古生物学家不只是想要区分恐龙是食草还是吃肉，他们还想知道恐龙的具体饮食。这种更精细的研究决心需要直接的恐龙食物的化石证据。胃里的食物很少能保存，但如果有，就能让我们确定恐龙到底吃什么。
腔骨龙（一种体型较小、脖子较长的恐龙）的胃内食物样本是同类恐龙的幼崽骨头。科学家一度认为这些幼崽骨头属于腔骨龙的胚胎，认为这种小恐龙是胎生而非卵生。进一步的研究发现，这些幼崽体积太大，而且发育良好，不可能是孵化前的幼崽。另外，这些胃内的幼崽残骸大小也不一。所有的证据都表明，这些都是猎物的残骸，成年腔骨龙中至少有一部分是吃自己的同类的。
并非只有食肉恐龙才有胃内食物的化石。在一些罕见的情况下，鸭嘴龙的体内也发现有植物遗骸的化石或“木乃伊”（罕见的保存完好的标本）。一些古生物学家认为，这些食物是积累下来的食物而不是最后一餐。最著名的案例是施特恩伯格一家收集的第二具埃德蒙顿木乃伊。标本存放在德国森肯伯格博物馆内，在其胸腔内，是针叶、细枝、种子和果实的化石。加拿大阿尔伯塔的冠龙标本也报导了类似的发现，这表明至少有两种晚白垩纪的鸭嘴龙是以现在北半球森林中的常见树木为食的。
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另一个直接的证据形式来自粪化石（身体排泄物的化石）。几个恐龙化石地点保存有粪化石。粪化石能明确说明恐龙的饮食习惯。很多植物和动物不容易被动物的消化系统消化，没有改变或者只有些许改变就排出体内了。对粪化石的研究表明，有些食草恐龙的饮食比较多样化，而另一些恐龙似乎专门吃某些特定的食物。从粪化石推断饮食偏好，困难在于如何准确知道哪种粪化石属于哪种特定的恐龙。
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.
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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.
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
3. The word “retarded” in the passage is closest in meaning to A. disguised B. added to
C. made possible D. slowed down
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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.
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.
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.
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
11. The word “pronounced” in the passage is closest in meaning to A. examined