Have you ever walked outside thinking it was one temperature but quickly discovered it felt colder? That is because of the “wind chill” effect.
Wind chill is how cold people and animals feel when they are outside, not the actual temperature on the thermometer(温度计). It is based on how quickly your body loses heat when it is exposed to wind and cold. When the wind is strong, your body quickly loses heat, making the temperature of your skin drop.
When scientists first started calculating wind chill, they used research conducted in 1945 by explorers to Antarctica who measured how quickly water froze outside.
But water freezes faster than exposed skin, so the wind chill index based on that data wasn’t accurate.
In 2001, the US government began to measure wind chill more precisely by testing how quickly people’s skin froze.
Twelve volunteers were placed in a chilled wind tunnel. Equipment was stuck to their faces to measure the heat flow from their cheeks, forehead, nose and chin while they walked three miles per hour on a treadmill(跑步机).
The experiment revealed how quickly exposed skin can be damaged, particularly unprotected areas like your fingers, toes, the tip of your nose and your ear lobes. In fact, 40 percent of your body heat can be lost through your head! Signs you might have frostbite(冻疮) are when the skin turns white or pale and you lose feeling in that area.
The information collected from the volunteers helped scientists work out the math to compute wind chill. It involves wind speed and air temperature.
If, for example, the temperature outside is zero degrees Fahrenheit and the wind is blowing at 15 miles per hour, the wind chill is calculated at 19 degrees below zero. At that wind chill temperature, exposed skin can freeze in 30 minutes.
You can find a calculation table at www.nws.noaa.gov/om/windchill/index.shtml.
Experts advise in cold weather that you wear loose-fitting, lightweight, warm clothing, worn on top of each other. Air caught between the clothes will keep you warm. The best cold-weather coats have head coverings made of woven material that keep out water. So next time the temperature drops and you want to play outside, listen to your parents when they tell you to wrap up warm!
【小题1】 According to the text, wind chill _______.

A.means how fast exposed skin freezes
B.doesn’t affect your head as much as other body parts
C.changes according to the temperature on the thermometer
D.changes from person to person depending on their health
【小题2】 When might a person have frostbite according to the passage?
A.When his skin turns red and he loses feeling in that area.
B.When he is running faster and he is losing strength quickly.
C.When his face is exposed and quickly loses heat even indoors.
D.When his skin turns pale and he has no feeling in that area.
【小题3】 What factors influence wind chill?
A.A person’s body temperature and will speed.
B.Wind speed and a person’s strength.
C.Air temperature and wind speed.
D.The location and air temperature.
【小题4】 What can we conclude from the passage?
A.It was in 1945 that scientists first began to calculate wind chill.
B.Compared with water, people’s exposed skin freezes more slowly.
C.The wind chill index based on Antarctica data is considered a standard.
D.With the development of technology, many previous researches have been proven wrong.


We all know something about Thomas Edison. He was a great American   21  .He was in school for only a short time.  22 , he had to leave the school and   23  himself at home and learned a lot. When Edison grew up, he had his own lab. He worked hard and hardly   24  to have a rest.
One day a friend of his brought a young man into his lab. He   25  the young man to Edison. He said the young man had studied in a famous university in Germany and had a lot of   26  of physics and maths. Edison was glad to work with a man like him and   27  him as a helper. A few weeks later, the young   28  about Edison’s past. He began to look down on him. Edison   29  about it, but he said   30  .
Once the young man came into the lab while Edison   31  an important experiment. He stood near the table   32  he didn’t help him. Edison stopped   33  out a bottle and said, “Go to calculate (计算)its volume(容积)and tell me the   34  in two hours.”
At first the young man thought it easy to do it. Soon he   35  it difficult. Two hours later Edison went into his office and saw a lot of paper and books on his desk. Of course he couldn’t compute the volume in the time   36  .
“Why not pour some   37  into the bottle?” said Edison. “Then you’ll   38  calculate its volume!” Having heard this, the young man’s   39  turned red, and he knew Edison was really   40 than him!

【小题1】
A.doctorB.playerC.writerD.inventor
【小题2】
A.SoonB.AfterC.Later onD.Soon after
【小题3】
A.teachB.play withC.studyD.enjoy
【小题4】
A.forgotB.rememberedC.finished D.observed
【小题5】
A.showedB.pushedC.introducedD.threw
【小题6】
A.newsB.booksC.knowledgeD.dictionaries
【小题7】
A.employedB.askedC.madeD.watched
【小题8】
A.beardB.learnedC.readD.told
【小题9】
A.toldB.was toldC.saidD.was said
【小题10】
A.somethingB.everythingC.nothingD.all
【小题11】
A.didB.hadC.was doingD.was having
【小题12】
A.but B.andC.as D.while
【小题13】
A.bringingB.to bringC.takingD.to take
【小题14】
A.resultB.way C.ideaD.opinion
【小题15】
A.knewB.sawC.learnedD.found
【小题16】
A.givenB.followedC.saidD.taken
【小题17】
A.oilB.saltC.waterD.food
【小题18】
A.carefullyB.slowlyC.easilyD.quietly
【小题19】
A.headB.faceC.eyesD.ears
【小题20】
A.more politeB.stricterC.more kind-heartedD.cleverer

The home computer industry has been growing rapidly in the United States for the last ten years . Computers used to be large, expensive machines that were very difficult to use . But scientists and technicians have been making them smaller and cheaper while at the same time they have been made easier to use. As a result, their popularity has been increasing as more people have been buying computers for their homes and businesses. Computers have been designed to store information and compute problems that are difficult for human beings to work out. Some have voices that speak with the operators. Stores use computers to keep records of their inventories(库存货物) and to send bills to their customers(顾客) . Offices use computers to copy letters, record business and keep in touch with other offices. People have been using computers in their homes to keep track of the money they spend.

    One important new use for computers is for entertainment(娱乐). Many new games have been designed to be played on the computers. People of all ages have been playing these games, People also have been buying home computers to play computer games, watch movies and listen to concerts at home. They have become very popular indeed.

1. Computers used to _____.

A. work rapidly                  B. be large and expensive

C. be easy to use                 D. be used for fun

2. In recent years , computers are being made ______.

A. larger and more expensive        B. smaller and cheaper

C. more difficult to use             D. to work more slowly

3. Home computers can be used for ______.

A. writing letters        B. playing games

C. doing business        D. all of the above

4. Salesmen use computers mainly to ______.

A. check the list of goods and materials that are kept in the store house

B. play games for pleasure

C. talk with their friends 

D. write letters

 

D

A mysterious machine found in a 2,000-year-old Greek shipwreck may have been used to calculate the positions of planets, predict when eclipses (日、月蚀) were to occur, and study other parts of astronomy (天文学). When it was found underwater about 100 years ago, the machine was in poor shape. Its metal pieces had become one mass (堆), and then broke into pieces.

When the researchers began to study what was left of the machine, they thought it might have something to do with astronomy. To find out more, they recently used advanced imaging methods, including X-ray computer tomography (断层摄影术), to look inside the metal parts and to check for ancient writing on the machine.

According to their research, the researchers believed that this machine could have been used to compute eclipses of the sun and moon and was also able to show the movements of planets. A user could pick a day in the future and, work out a planet’s position on that date by moving some sort of crank (曲柄) on the machine.

Besides, the researchers discovered that the machine had at least 30 bronze gears (齿轮) with as many as 225 teeth, likely all cut by hand.

With all the collected information, the researchers came up with a new model for how the machine operated. The model has 29 of the 30 known gears and five more that were probably there but never found. Also,the new picture adds a previously undiscovered spiral dial (螺旋刻度盘) to the back of the machine near the bottom. A hand moving around the dial could have pointed to eclipses over a period of 18 years.

71. The passage is most probably taken from _____.

A. a short-story collection

B. a popular science magazine

C. a political report

D. an old personal diary

72. What is the passage mainly about?

A. New research on calculating the positions of planets.

B. A popular way of computing eclipses of the sun and moon.

C. Scientists’ interest in the secrets of a 2,000-year-old Greek shipwreck.

D. A mysterious machine which could be used for astronomical research.

73. What do we learn from the third paragraph of the passage?

A. The machine might have been used to calculate the positions of the planets.

B. Scientists made great progress in predicting eclipses of the sun and moon.

C. The researchers discovered some secrets in the Greek shipwreck.

D. The machine can be of great help for people working out the sizes of planets.

74. The researchers made a new model because they____.

A. wished to repair the broken machine

B. wanted to study the shipwreck more conveniently

C. hoped to know how the machine worked

D. expected it to be used in modern scientific research

75. Which of the following statements is TRUE about the old machine?

A. It has 35 gears on it.

B. It has a spiral dial.

C. It was invented about 100 years ago.

D. Its gears have many teeth.

 

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