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  3. You will listen to part of a lecture and answer a question about it. After you hear the question, you will have 20 seconds to pr

You will listen to part of a lecture and answer a question about it. After you hear the question, you will have 20 seconds to pr

admin2022-05-28  66
问题 You will listen to part of a lecture and answer a question about it. After you hear the question, you will have 20 seconds to prepare a response and 60 seconds to record the response.
Now listen to part of a lecture in a geology class.
Using points and examples from the lecture, describe two contributing factors to urban heat island effect.
Now listen to part of a lecture in a geology class.
    Have any of you ever noticed how cities and urban areas seem much hotter than rural areas? It may surprise you to find out that there’re many well-documented reasons for this phenomenon, which in the scientific community is called urban heat island effect. An urban heat island is a metropolitan area that’s significantly warmer than its surrounding rural areas due to human activities. There’re several factors that contribute to the drastic temperature difference between urban and rural areas. Let’s look at two examples so that you can better understand what an urban heat island is.
    One factor that contributes to hotter cities is the construction materials used for houses, roads and other urban developments that have very different thermal properties and coloration compared to grass and other vegetation. As a result, more of the incoming solar energy goes directly to heating the blacktop roads, concrete sidewalks and buildings in cities. Additionally, objects dark in color will absorb more sunlight than light-colored objects. This allows the air temperature to rise more rapidly in the cities. During night, the stored heat energy in roads and other structures is slowly released into the air, which slows the cooling process. This keeps cities warmer than rural areas at night as well as during the day.
    Another contributing factor to urban heat island effect is heat emissions from machinery. Vehicles, factories and air conditioners add more heat to the atmosphere and further intensify the heat island effect. Vehicles in particular have a significant impact on heat island effect. Firstly, heat is a byproduct of engine combustion, meaning that a running car will produce heat. Secondly, vehicle emissions, gases that are a result of combustion, contribute to the greenhouse gas effect and further exacerbate the problem of urban heat islands. It’s no wonder that when summer comes, a lot of people leave the city for a short vacation to escape the heat.
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答案 Urban heat island effect is the phenomenon that the temperature of urban areas becomes much higher than that of rural regions. Two factors bring about this effect. One is the construction materials used for houses and roads. Their thermal properties make them easier to be heated by sunlight than vegetation. And these materials usually have a dark color, which facilitates heat absorption. The heat stored in them will be released at night, slowing down the cooling process. The other contributing factor is the heat emissions by machines and vehicles. Air conditioners, automobiles, and factories release a large amount of heat to the atmosphere. What’s more, car engines also emit greenhouse gases that exacerbate the urban heat island effect.
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