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红DeltaTest2综合写作Summarize the points made in the lecture you just heard, explaining how they contrast with points made in the reading.作文范文+答案解析

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Directions: You have 20 minutes to plan and write your response. Your response will be judged on the basis of the quality of your writing and on how well your response presents the points in the lecture and their relationship to the reading passage. Typically, an effective response will be 150 to 225 words.
Summarize the points made in the lecture you just heard, explaining how they contrast with points made in the reading.
题目原文:
A hydropower facility consists of a plant for electricity production and a water reservoir formed by a dam in a river. The dam has gates that can open or close depending on how much water is needed to produce a certain amount of electricity. The electricity is transported through transmission lines to an electric utility company.Hydropower is very convenient because it can respond quickly to fluctuations in demand. The production of hydroelectricity is increased on hot summer afternoons when power is needed for air conditioners and decreased at night when people use less energy. The reservoir of water behind the dam is stored energy that can support fisheries and provide various forms of water-based recreation for local residents and tourists. Thus, hydropower reservoirs contribute to the local economy and quality of life.Hydroelectricity is “clean and green.” Once the system has been installed, the burning of fossil fuels is not required to produce the electricity. Hydropower is good for the environment because it does not release greenhouse gases into the atmosphere nor produce waste that requires special containment, as do other forms of energy production. After the water powers the turbines, it simply returns unchanged to the water cycle.Hydroelectric power is also very efficient and relatively inexpensive. The earth’s water cycle naturally replenishes the supply of “fuel” water. Wherever enough rain falls, there will be rivers. If a particular section of river has the right terrain to form a reservoir, it may be suitable for dam construction. Modern hydroelectric turbines can convert as much as 90 percent of the available energy into electricity. In contrast, the best fossil-fuel plants are only about 50 percent efficient.
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听力原文

The advantages of hydropower are well known, but there are also some serious disadvantages that should cause us to rethink its overall benefit.

First, hydropower facilities are not always convenient for everyone involved. When a dam is built on a river, water floods the land behind the dam. This forces the people who live in the flooded area to move. Forcing people to move is often bitter and controversial, especially if a community has maintained a particular way of life on the same land for several generations.

Second, utility companies often emphasize that hydroelectricity is environmentally friendly, “clean and green,” but they fail to mention the long-term environmental hazards. Dams hold back silt and other debris, which collect behind the dam on the river bottom. This causes an accumulation of toxic heavy metals and other polluting substances, showing us that, hydropower does indeed produce toxic waste. The buildup of silt means that future generations will have an expensive and dangerous mess to clean up.

Third, the huge dams built for hydroelectricity change a river’s natural functions. By diverting water for power, dams remove water needed for healthy river ecosystems. The section of river below a dam often dries up, and birds that migrate there no longer have enough insects to feed on when the water level drops. Also, fish such as salmon depend on a steady flow of cool, fresh water. Native fish populations may decrease or disappear because of the warmer and slower-moving water caused by dams. The environmental changes caused by hydropower may not be obvious right away. Most people will notice air pollution around a coal-burning power plant, but they won’t notice a smaller bird population near a hydropower plant.

While it’s true that hydropower is a renewable energy source, it often carries a heavy environmental cost.

Furthermore, even though water is a naturally recurring product, the water supply is subject to natural conditions, such as changing weather patterns and regional drought, so water as a source of fuel may not be reliable in the long run.

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