radiation n. 辐射.放射 查看更多

 

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A Concussion(脑震荡) happens when the brain is shaken, often in a car crash or a fall or a strike on; the head in sports.Concussions can be mild, but doctors may order a CT scan to look for a more serious injury.But a recent study warned that more children than necessary are being exposed(使遭受) to radiation this way.

A national team led by two doctors at the University of California, Davis, studied hospital records from thousands of children with head injuries. They found that in many cases, the risk of developing cancer from the radiation outweighed the risk of a serious brain injury.

The study found that one in five children over age two had a low risk of serious injury but received CT scans anyway. The same was true of almost one in four children under two years of age.

The researchers have developed rules to predict if a head injury is serious enough for a scan. For children under two, doctors are advised against it if there is:

·Normal mental activity.

·No swelling in the back of the head.

·No feeling of a broken bone in the skull. (头骨)

·And no loss of consciousness for more than five seconds.

Doctors should also consider how the child was injured and whether the parents say the child is acting normally.

For patients from two to eighteen, the guidelines are similar —— except there should be no l vomiting(呕吐)and no severe headache.

Earlier this year, the British Journal of Sports Medicine published new guidelines for concussions in children and teens. International experts said they should not return to sports or school until fully recovered. The brain also needs a "cognitive rest," they say, by restricting activities like video games, texting and watching TV.

It often take longer than adults to recover from a concussion than adults. The experts say individual progress and not a set time period should always guide a decision to return to play.

The researchers at the -University of California found that children who received CT scans

       A.were likely to suffer brain injuries 

       B.wouldn't have normal mental activity

       C.would lose consciousness now and then 

       D.were likely to develop canter

How many aspects should doctors consider when deciding whether a child under two needs a CT scan?      

       A.Four.     B.Six.       C.Seven.   D.Nine.

What can we learn from the last two paragraphs?

       A.Texting is harmful to patients’ recovery from concussions.

       B.Patients with brain injuries can play many sports.

       C.Adults need a longer time than teens to recover from concussions.

       D.It takes at least a year for individuals with brain injuries to fully recover.

The author of the passage mainly___.

       A.describes the risks of brain injuries

       B.suggests CT scans are of practical use

       C.tells us about the risks of brain injury tests

       D.argues against new guidelines for concussions

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Modern inventions have speeded up people’s loves amazingly. Motor-cars cover a hundred miles in little more than an hour, aircraft cross the world inside a day, while computers operate at lightning speed. Indeed, this love of speed seems never-ending. Every year motor-cars are produced which go even faster and each new computer boats (吹嘘) of saving precious seconds in handling tasks.

All this saves time, but at a price. When we lose or gain half a day in speeding across the world in an airplane, our bodies tell us so.  We get the uncomfortable feeling known as jet-lag; our bodies feel that they have been left behind on another time zone. Again, spending too long at computers results in painful wrists and fingers. Mobile phones also have their dangers, according to some scientist; too much use may transmit harmful radiation into our brains, a consequence we do not like to think about.

However, what do we do with the time we have saved? Certainly not relax, or so it seems. We are so accustomed constant activity that we find it difficult to sit and do nothing or even just one thing at a time. Perhaps the days are long gone when we might listen quietly to a story on the radio, letting imagination take us into another world.

There was a time when some people’s lives were devoted simply to the cultivation of the land or the care of cattle. No multi-tasking there; their lives went on at a much gentler pace, and in a familiar pattern. There is much that we might envy about a way of life like this. Yet before we do so, we must think of the hard tasks our ancestor faced: they farmed with bare hands, often lived close to hunger, and had to fashion tools from wood and stone. Modern machinery has freed people from that primitive existence.

1.The new products become more and more time-saving because         .

A. our love of speed seems never-ending

B. time is limited.

C. the prices are increasingly high.

D. the manufactures boast a lot.

2.What does “the days” in Paragraph 3 refer to ?

A. Imaginary life                             B. Simple life in the past.

C. Times of inventions                        D. Time for constant activity.

3.What is the author’s attitude towards the modern technology?

A. Critical             B. Objective.     C. Optimistic.      D. Negative.

4.What does the passage mainly discuss?

A. The present and past times.

B. Machinery and human beings.

C. Imaginations and inventions.

D. Modern technology and its influence.

 

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完成句子 根据提供的意思,完成句子。(共10分,每格0.5分)

1.他病得如此严重以致他是否回来还不清楚.

He is so seriously ill that ___ was not clear ____   ____   ____ he will come.

2.太空飞船使我们到月球旅游成为可能.

Spaceship ______  ________  ________  for us to travel to the moon.

3.由于核辐射,很多日本人担心安全问题.

______   _______    ______    _______ nuclear radiation, many Japanese are worried about safety.

4.我正要说出真相这时他打断我.

I ______   ______    ______ tell the truth  _____  he interrupted me

5.老师不允许学生考试作弊逃脱惩罚.

The teacher won’t _____ students ______   ______   ______   _______ in the exam.

 

 

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Geena David knew she wanted to be a movie star when she was very young. She was not sure what gave her the idea, but she wanted to look like a movie star. “I have a lot of pictures from my childhood of me wearing sunglasses,” she ways. “I used to wear them to watch TV.”

    Early movie actors started wearing sunglasses not because they looked good, but because their eyes hurt. The lights used on movie sets were extremely bright and could cause a painful problem known as “Klieg eyes”. It was named after the Klieg brothers who invented the lights. Actors wore sunglasses to give their eyes a rest. But when movie stars began wearing their sunglasses in public, they quickly became a must.

    Eventually actors started wearing sunglasses in their movies as well as on the street. Audrey Hepburn wore ultra-cool Ray-Ban sunglasses in the 1961 movie, Breakfast at Tiffany’s. As a result, Ray-Ban sunglasses started to appear more and more in the movies. In 1979, Ray-Ban “Wayfarers” were worn by Jake and Elwood in The Blue Brothers. Tom Cruise wore Ray-Ban “Aviator” sunglasses in the 1986 hit, Top Gun. Then in 1997, Will Smith and Tommy Lee Jones made Ray-Ban “Predator” sunglasses famous in Men in Black.

    Of course sunglasses aren’t just a fashion statement. The main reason to wear sunglasses is to protect our eyes against UV radiation. UV radiation can damage our eyes, so people now choose their sunglasses carefully. But you don’t have to give up style for safety. The choice of frames and lenses available these days is huge. So you can protect your eyes and still be the coolest person on the beach.

1.  What is mainly discussed in this passage?

    A. The use of sunglasses.                   B. The history of sunglasses.

    C. The sunglasses wearing.                  D. Why movie stars like to wear sunglasses.

2.  Why did Geena David like to wear sunglasses?

    A. She was a movie star.                        B. She wanted to follow a movie star.

    C. Wearing sunglasses was good to her eyes.     D. It was good wear sunglasses when watching TV.

3.  Early actors’ eyes hurt because _______.

    A. they wore sunglasses.                        B. they went out in the sun too much

    C. the lights on movie sets were too bright     D. their scripts were written in very small writing

4.  We may know from this passage that _______.

    A. Audrey Hepburn was a famous film star       

B. Ray-Ban is the name of sunglasses maker

    C. sunglasses made Top Gun the hit in 1986     

D. Men in Black must be an advertisement of sunglasses

 

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Scientists believe that conditions on Mars around 3.8 billion years ago were very similar to those of the early earth, when primitive organisms were spreading through our oceans. At that time, Mars would have been much warmer and wetter than it is today, with an atmosphere composed mainly of carbon dioxide, just like that of the earth at the time. Under these conditions, it is highly probable that life may have arisen on Mars as well.

  But, even if life did not arise naturally on Mars, it does not mean that it could not have existed there. According to Professor Paul Davies of the University of Adelaide, Australia, life forms could have been transferred between the earth and Mars in wreckage (broke pieces) created by the impact of comet(彗星) and small planets on the surface of the two planets.

  Even today, about 500 tons of material from Mars lands on earth every year. It is mainly in the form of the dust but occasionally a larger chunk(厚片,大块) strikes the earth. In 1911, a piece of Martian rock crashed in Egypt, killing a dog. According to Professor Davies, it is in these chunks of rock, which were much larger and more frequent in the past that life forms could have been transported from planet to planet.

  “But how could these life forms have survived their journey through space?” says Paul Davies, “The difficulty in believing this theory is that a bacterium on its own in space has to struggle itself not only against cold but also against deadly cosmic (宇宙的) radiation. But wrapped in a rock the situation is different. A rock ten meters across would shield life inside it from a lot of radiation and the temperature might only be minus 10 or 20 degrees, the sort of thing we have on earth.”

Where do some scientists suppose life probably come from? (2’) (No more than 6 words)

What does Professor Paul Davies believe? (2’) (No more than 6 words)

Why could life survive when transferred from one planet to another? (3’) (No more than 12 words)

List at least two differences about Mars between the past and now. (3’) (No more than 16 words)

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