Adamisaman-madestructurebuiltacrossariver.Mostdamsarebu...
問題詳情:
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(水輪機). Turbines contain metal coils(線圈) surrounded by magnets(磁鐵). 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.
4. 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.
5. 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
dam which controls the Colorado river is ____.
A. the Oroville Dam B. the Hoover Dam C. the Nurek Dam D. the Vakhsh Dam
【回答】
CAB
知識點:閱讀理解
題型:閱讀理解
-
下列離子方程式的書寫正確的是( )A.過量C02通入*氧化鈣溶液中:CO2+OH﹣═HCO3﹣B.Na202...
問題詳情:下列離子方程式的書寫正確的是()A.過量C02通入*氧化鈣溶液中:CO2+OH﹣═HCO3﹣B.Na202加入H2180中:2Na2O2+2H218O═4Na++4OH﹣+18O2↑C.矽與***的反應:Si+4H++4F﹣═SiF4↑+2H2↑D.水玻璃中通人過量二氧化碳:Na2SiO3+CO2+H2O═2Na++CO32﹣+H2SiO3【回答】【考點】離子方程...
-
我國現存最早的數學名著是A.《九章算術》 B.《綴術》 C.《大明曆》 ...
問題詳情:我國現存最早的數學名著是A.《九章算術》 B.《綴術》 C.《大明曆》 D.《水經注》【回答】A知識點:大河流域人類文明的搖籃題型:選擇題...
-
近日我州某地成功處置了一輛滿載三*化*(PCI3)的車輛洩漏事故.三*化*是一種重要的無機鹽工業產品,無*液體...
問題詳情:近日我州某地成功處置了一輛滿載三*化*(PCI3)的車輛洩漏事故.三*化*是一種重要的無機鹽工業產品,無*液體、密度1.574g/cm3(21℃),熔點﹣112℃,沸點75.5℃,易燃.遇水反應生成亞**(H3PO3)和*化*,與有機物接觸會著火.下列對三*化*的說法錯誤的是()A.三*化*中*元素的化合價為+...
-
根據句意及首字母,寫出單詞,使句子意思完整1.Mym________birthdayisDecember13t...
問題詳情:根據句意及首字母,寫出單詞,使句子意思完整1.Mym________birthdayisDecember13th.2.Ilikep________music.3.Shew________toplaybaseball.4.Thelittleboywantssomec________.5.MissWangiso________musicteacher.6.Doyouwanttoplaywiththedogn________?7.Let'sp_...
相關文章
- 完形填空 Severaldaysago,somestudentsfromtheUSvisitedoursc...
- A“smartdrug”takenbystudentstoimprovetheirperformancerea...
- Myuncleisabusdriver.Hegoestoworkataquartertosixinthemor...
- Europe’sMarsorbiter(人造衛星)hasfoundwatermolecules(分子)vapo...
- Youmaybesurprisedtosee“makingsurechildrenneversuffer”as...
- MyparentsandtwoolderbrothersarrivedinQueensfromCubain19...
- Whileyouaretravellingabroad,culturalmistakesaremoreseri...
- (2018·全國卷Ⅱ)SummerActivitiesStudentsshouldreadthelistwit...
- BasicStudyManual(Hardcover):$37.50Futuresuccessdependso...
- Weliveinaculturethatsendsoutverymixedmessagesaboutmista...