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(jī)). 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.

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

練習(xí)冊(cè)系列答案
相關(guān)習(xí)題

科目:高中英語 來源:湖北省天門、仙桃、潛江三市2016-2017學(xué)年高二下學(xué)期期末考試英語試卷 題型:閱讀理解

Anyone who has ever played the game of Tetris (俄羅斯方塊) knows the game’s surreal ability to spill into real life. After you shut off the game, you still see those Tetris blocks falling in your mind. You're grocery shopping and find yourself thinking about rearranging items on grocery shelves. Your mind continues to play the game, even when you're physically not.

Robert Stickgold, a Harvard professor, noticed something similar after a day hiking a mountain. That night, he dreamt he was still going through the motions of mountain hiking. Curious about this, he tried something: he got a group of college students of various skill levels to play Tetris and let them sleep in the Harvard sleep lab.

Over 60% of the students, including those who suffered from amnesia (健忘癥), reported dreams of images of Tetris pieces falling, rotating (旋轉(zhuǎn)), and fitting together. Interestingly, half the Tetris expert students reported such Tetris dreams, while 75% of the beginners did.

A study found that playing Tetris can grow your brain and make it more efficient. Adolescent girls played the game for an average of 1.5 hours a week over three months. The cerebral cortex (大腦皮層) of the girls grew thicker, while brain activity in other areas decreased. Richard Haier, who had found that there was a "Tetris learning effect", in which the brain consumed less energy as mastery of the game rose, concluded, "The brain is learning which areas not to use."

Haier's study showed that as the girls practiced playing the game, nerve cells made connections, communicating through synapses (a synapse is a connection between two nerve cells). When you learn something, you change those connections. Every time you reactivate(激活) a circuit, synaptic efficiency increases, and connections become more durable and easier to reactivate. Stickgold says sleep plays a role in this memory process.

So to sum up, whenever you do specific tasks over and over again, they take up less of your brain power over time. And that’s pretty amazing.

1.What does the underlined part ‘surreal ability’ in the first paragraph mean?

A. The game can help people arrange things in life.

B. The game can be applied to many aspects of life.

C. There are great similarities between the game and things in life.

D. The mind continues to play the game when we are doing other things.

2.What can we learn from Stickgold’s study?

A. More than half of the students dreamed of images of Tetris.

B. Students having bad memories didn’t dream of the game.

C. The Tetris expert students were more likely to dream of the game than the beginners.

D. More than half of the Tetris expert students didn’t dream of the game.

3.Playing Tetris for a long time can help ________.

①grow one’s brain

②one’s brain function efficiently

③arrange things tidily in life

④improve the adaptability of one’s brain

A. ①②③ B. ①②④

C. ②③④ D. ①③④

4.The purpose of the passage is to ________.

A. encourage people to play Tetris

B. warn people to focus while doing things

C. warn people not to play games before sleep

D. tell people they will improve at something if they keep doing it

查看答案和解析>>

科目:高中英語 來源:內(nèi)蒙古包頭市2016-2017學(xué)年高一下學(xué)期期末考試英語試卷 題型:完形填空

I will have a holiday next week and I can’t decide what to do. I have a lot of work to do ___________ and this would be a good chance ___________. But I don’t like ___________ the holiday in such a way.I can work at home all the rest of the year.

Last year I went ___________ to the mountains. ___________ there was beautiful, but it is too cold this time of a year. And it’s really___________ far to go for a short holiday. I decide ___________ this isn’t a good time to___________the mountains.But I___________to go somewhere else.Perhaps this would be a good chance to go to the beach(海濱).I like to go for walks___________the seashore ___________the warm sunshine and watch the water. It’s only eight miles away and I could get there ___________about two hours. After thinking it___________,I am sure that this is a ___________time for the seashore than___________ .

Oh, here is a ___________ from Jim. He ___________ he is going to his house in the mountains for the___________,and he___________ me to go with him.___________ giving it some more thought, I wrote back to Jim and thanked him for that.

1.A. at home B. at house C. in school D. in factory

2.A. do it B. doing that C. to do it D. with that

3.A. to take B. to spend C. having D. asking

4.A. the north B. for north C. north D. to north

5.A. Nothing B. Everything C. Somebody D. Anything

6.A. very B. enough C. rather D. too

7.A. that B. what C. whether D. when

8.A. go B. go to C. go for D. leave

9.A. want B. wanted C. shall want D. was wanting

10.A. on B. by C. beside D. along

11.A. on B. during C. in D. under

12.A. in B. for C. with D. after

13.A. about B. of C. over D. on

14.A. good B. fine C. better D. best

15.A. home B. the mountains C. big cities D. country villages

16.A. gift B. call C. letter D. notice

17.A. says B. tells C. speaks D. talks

18.A. weekend B. holiday C. Sunday D. trip

19.A. want B. wish C. hopes D. asks

20.A. When B. With C. Without D. As

查看答案和解析>>

科目:高中英語 來源:安徽省宣城市2016-2017學(xué)年高一下學(xué)期期末調(diào)研測(cè)試英語試卷 題型:七選五

With time going by, people have come to understand the importance of protecting the environment. But they can’t deal with everything by themselves. Take small steps, and you can make a difference.

• Think Green. Think about the environment as you live your life. If you turn off lights and TV when leaving the room, you’ll save energy. 1..

• Shop Green. Shopping is fun, but buying things you don’t need is wasteful and even bad for the earth. 2.. And whenever possible, buy things locally made instead of those shipped from far away.

• Dress Green. What really matters is not the colour. 3.. So look for products made from environmentally friendly (環(huán)保的) materials.

4.. What’s better than learning about the environment? 5.. It can be as simple as using both sides of a piece of paper before you recycle it

A. Before you buy something, ask yourself how much you will use it.

B. Study Green.

C. It’s how the clothes were made.

D. You may care more about the qualities of the clothes.

E. Save it while you learn.

F. If you take shorter showers, you will save water.

G. Recycle more.

查看答案和解析>>

科目:高中英語 來源:山西省2016-2017學(xué)年高二下學(xué)期期末考試英語試卷 題型:短文填空

In my free time, I really like surfing the Internet.When I get home from work, I turn on my computer, wait 1.it boots up completely, and then I go online.I usually check my email first and then write a few messages 2. family and friends.I sometimes scan the local news headlines at 3. (me)favorite news Website and read up on the latest local and international news.This Website often provides video news clips that 4.can view online.I sometimes order products or service online to save money and time instead of going to a store and 5. (buy)what I'm looking for.For example, 6. (order)a digital camera online the other day and saved about $50.Whatever I do, I realize that there are problems 7.using the Internet including scams, identify theft, and viruses, so I'm very careful not to give out my 8. (person)information.Furthermore, I don't download or open files I don't recognize.Using the Internet can be fun and 9.convenient way of shopping and finding out new information, 10.you just need to be careful.

查看答案和解析>>

科目:高中英語 來源:陜西省延安市大學(xué)區(qū)校際聯(lián)盟2016-2017學(xué)年高二下學(xué)期期中考試(B)英語試卷 題型:單詞拼寫

1.___________(浪漫主義的)poems are always popular with the youth.

2.All students without ______________(例外) must take the English examination.

3.I ___________(驚慌) when I saw smoke coming out of the engine.

4.Our English teacher is always ___________ (優(yōu)雅地) dressed.

5.Many people went to California during the 1900s to make a _____________(財(cái)富).

6.You all know who I am ___________(提及) to when I say “that nice man”.

7.The man must do many things, ________(包括) directing the traffic.

8.Early _______________(移民者) on the American continent were mostly Europeans.

9.The Sprifg Festival is the most important __________ (傳統(tǒng)) festival in China.

10.Did you go to watch the football match held in the _____(體育場(chǎng))

查看答案和解析>>

科目:高中英語 來源:安徽省蚌埠市2017屆高三7月月考英語試卷 題型:短文改錯(cuò)

假定英語課課上老師要求同桌之間交換修改作文,請(qǐng)你修改你同桌寫的以下作文。文中共有10 處語言錯(cuò)誤,每句中最多有兩處。每處錯(cuò)誤僅涉及一個(gè)單詞的增加、刪除或修改。 增加:在缺詞處加一個(gè)漏字符號(hào)(∧),并在其下面寫出該加的詞。

刪除:把多余的詞用斜線(\)劃掉。

修改:在錯(cuò)的詞下畫一橫線,并在該詞下面寫出修改后的詞。

注意:1.每處錯(cuò)誤及其修改均僅限一詞;

2.只允許修改 10 處,多者(從第 11 處起)不計(jì)分。

We are aiming to build a peaceful school. I thought it is every student’s duty to work hard to achieve this goal. As high school student, what should we do? First for all, we should love our school. Meanwhile, you should respect our teachers and obeying the rules in our school. Secondly, we should show our respect for our parents and do which we can help them. Besides, we classmates should also try to be kind and friendly. Most important, all of us must believe in each other and been honest in our daily life. And we will study even more harder and try out best to do all.

查看答案和解析>>

科目:高中英語 來源:黑龍江省2016-2017學(xué)年高一下學(xué)期期末考試英語試卷 題型:書面表達(dá)

臨近期末,高一同學(xué)即將面臨著文理分科的選擇。假定你是李華,你同學(xué)Lucy給你來信說到了她對(duì)文理科選擇的困擾和焦慮。請(qǐng)你給她回信,安撫她的情緒并提出你的看法和建議。

注意:

1. 詞數(shù)100左右; 書信開頭和結(jié)尾已給出,不計(jì)入總詞數(shù)。

2. 內(nèi)容要點(diǎn):

① 安撫她的情緒,勸她不必過于糾結(jié);

② 提出參考意見:認(rèn)清自己興趣和優(yōu)勢(shì),不盲從他人;向高年級(jí)的同學(xué)請(qǐng)教 ……

③ 提出看法:無論作何選擇都要努力才能實(shí)現(xiàn)自己的期望。

3. 可以適當(dāng)增加細(xì)節(jié),以使行文連貫。

可能用到的詞匯:焦慮anxiety;理性地 rationally;不辜負(fù) live up to 盲目地 blindly

Dear Lucy,

I’m sorry to learn in your letter that you are upset about the coming choice of arts or science. ____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

查看答案和解析>>

科目:高中英語 來源:內(nèi)蒙古包頭市2016-2017學(xué)年高一下學(xué)期第二次月考英語試卷 題型:閱讀理解

Want to find a job? Now read the following advertisements.
FAIRMONT HOTEL
Five waiters and Ten Waitresses
---Aged under 22
---At least high school graduate
---Good looking; men at least 1.72 meters tall and women 1.65
---Those knowing foreign languages preferred
---Paid 1600---2200 dollars per month
 One Secretary
---Aged under 30
---Female preferred
---Good at writing and skilled at computer
If interested, call 465-4768 or write to: Mr. Jack Hundris Room 0825, Fairmont Hotel
567 Wood Street, San Markers, 78003
Fax: 6954828
WILSON BOOKSTORE
Accountant(會(huì)計(jì))
---Aged between 25 and 40
---With an experience of at least two years
---With a degree and an accountant certificate(證書)
---Paid 3000-4000 dollars monthly
---With a knowledge of computer
Salesclerk
---Basic education of 12 years or more
---Good at computer
---Paid 1800-2200 dollars monthly
Tel: 447-4398          Fax: 3485269

1.If you don’t know how to use a computer, you can just apply for the position as _________ .

A. a secretary

B. a waiter or a waitress

C. an accountant

D. a salesclerk

2.If you want to get the position of accountant in Wilson Bookstore, you have to satisfy the following conditions EXCEPT  _________ .

A. being a woman

B. knowing well how to use a computer

C. having been an accountant

D. having an accountant certificate

3.If you want to try for a job in Fairmont Hotel, you  _________ .

A. have to be a woman and know foreign languages

B. should be a university graduate

C. have to be taller than 1.72 meters

D. should be younger than 30 years old

查看答案和解析>>

同步練習(xí)冊(cè)答案