题目内容
A dam is a man-made structure built across a river. Most dams are built to control a river’s water flow, improve navigation and control flooding. However, some dams are built to produce hydro-electric power.
Hydro-electric power is produced as water passes through a dam, and into a river below. The more water that passes through a dam, the more energy is produced. Once a dam is built, a man-made lake is created behind the dam.
Electricity is produced by a kind of equipment called a turbine(水轮机). Turbines contain metal coils(线圈) surrounded by magnets(磁铁). When the magnets move round rapidly over the metal coils, electricity is produced. Turbines are located inside dams. The falling water makes the magnets go around the coils.
Dams provide clean energy, but they can also harm the environment. Species that use rivers to reproduce are often hurt by dams. In the Northwest of the US, the population of fishes has dropped from 16 million to 2.5 million since hydro-electric plants were built on the Columbia River. Dams all over the world have hurt some species.
The highest dam in the Unites States is located near Oroville, California. The Oroville Dam towers 230 meters and is more than a mile wide. This dam was built in 1968, 22 years after the Hoover Dam. The Hoover Dam, on the Nevada-Arizona border controls the Colorado river. It is 221 meters high and has 2.6 million hectare-meters of water.
The highest dam in the world is the Nurek Dam on the Vakhsh River in Tadzikistan, a country in central Asia. This dam is 300 meters tall.
Which of the following statements is NOT true according to the passage?
A. Some dams are built for controlling a river’s water flow.
B. Hydro-electric power is usually produced through a dam.
C. Dams can offer energy and they are harmless to the environment.
D. Generally speaking, where there is a dam, there is a man-made lake.
The third paragraph mainly tells us _____. 56-60 ADB
A. how hydro-electric power is produced
B. What a turbine is and how it works
C. how the magnets and the metal coils work
D. how the falling water passes through a turbine
The dam which controls the Colorado river is ____.
A. the Oroville Dam B. the Hoover Dam C. the Nurek Dam D. the Vakhsh Dam
【小题1】C
【小题2】A
【小题3】B
解析:
【小题1】从第一段可知A项和B项对，从第二段的最后一句可知D项对， 从第四段的第一句话,but they can also harm the environment可知C项不对。
【小题2】这是一个主旨大意题，第三段主要告诉了我们水电是怎样通过一些设备产生电能的，故答案为A。
【小题3】从倒数第二段可找出答案为B。
Life on earth depends on water, and there is no substitute for it. The current assumption is that our basic needs for water — whether for drinking, agriculture, industry or the raising of fish will always have to be met . Given that premise (前提), there are two basic routes we can go: more equal access to water or better engineering solutions.
Looking at the engineering solution first, a lot of my research concentrates on what happens to wetlands when you build dams in river basins, particularly in Africa. The ecology of such areas is almost entirely driven by the seasonal changes of the river — the pulse of the water. And the fact is that if you build a dam, you generally spoil the downstream ecology. In the past, such problems have been hidden by a lack of information. But in the near future, governments will have no excuse for their ignorance.
The engineers’ ability to control water flows has created new kinds of unpredictability, too. Dams in Africa have meant fewer fish, less grazing and less floodplain (洪泛区) agriculture — none of which were expected. And their average economic life is assumed to be thirty years. Dams don’t exist forever, but what will replace them is not clear.
The challenge for the future is to find new means of controlling water. Although GM technology (转基因) will allow us to breed better dry-land crops, there is no market for companies to develop crops suitable for the micro-climates of the Sahel and elsewhere in Africa. Who is going to pay for research on locally appropriate crops in the Third World?
1.What’s the main idea of this passage?
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A．The engineering solutions to water resource and their limitation. |
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B．The challenge for the future. |
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C．The basic means of controlling water. |
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D．The challenge for developing crops. |
2. Which of the following statements is NOT true for meeting our basic needs for water?
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A．Water resource should be used more reasonably. |
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B．More dams should be built in river basins. |
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C．More wetlands should be protected from destruction. |
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D．More dry-land crops could be developed in Africa. |
3. The author suggests that governments will have no excuse for their careless ignorance in the future because .
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A．The ecological destruction will be known to the public by researchers |
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B．The ecological destruction will no longer be a problem in the future |
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C．The future is an information age |
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D．Governments will face greater challenge in the future |
4.The author mentions all the problems caused by dams EXCEPT .
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A．fewer fish |
B．less grazing land |
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C．less floodplain agriculture |
D．less farming land |
5.The last sentence probably implies that .
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A．No one will invest in developing locally appropriate crops in Africa |
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B．Researchers have no interest in developing dry-land crops |
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C．Research on locally appropriate crops in the Third World may be profitable |
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D．There is less water resource in the Third Worldk*s*5u |
| A dam is a man-made structure built across a river. Most dams are built to control a river’s water flow, improve navigation and control flooding. However, some dams are built to produce hydro-electric power. Hydro-electric power is produced as water passes through a dam, and into a river below. The more water that passes through a dam, the more energy is produced. Once a dam is built, a man-made lake is created behind the dam. Electricity is produced by a kind of equipment called a turbine(水轮机). Turbines contain metal coils(线圈) surrounded by magnets(磁铁). When the magnets move round rapidly over the metal coils, electricity is produced. Turbines are located inside dams. The falling water makes the magnets go around the coils. Dams provide clean energy, but they can also harm the environment. Species that use rivers to reproduce are often hurt by dams. In the Northwest of the US, the population of fishes has dropped from 16 million to 2.5 million since hydro-electric plants were built on the Columbia River. Dams all over the world have hurt some species. The highest dam in the world is the Nurek Dam on the Vakhsh River in Tadzikistan, a country in central Asia. This dam is 300 meters tall. 1. Which of the following statements is NOT true according to the passage? A. Some dams are built for controlling a river’s water flow. B. Hydro-electric power is usually produced through a dam. C. Dams can offer energy and they are harmless to the environment. D. Generally speaking, where there is a dam, there is a man-made lake. 2. The third paragraph mainly tells us _____. A. how hydro-electric power is produced B. What a turbine is and how it works C. how the magnets and the metal coils work D. how the falling water passes through a turbine 3. The dam which controls the Colorado river is ____. A. the Oroville Dam B. the Hoover Dam C. the Nurek Dam D. the Vakhsh Dam |