US scientists have performed an important reversal（逆转） of the ageing process in animal studies. They used a chemical to rejuvenate（使年轻） muscle in mice and said it was the equivalent（等同于） of transforming a 60-year-old's muscle to that of a 20-year-old — but muscle strength did not improve. Their study, in the journal Cell, identified an entirely new mechanism（原理） of ageing and then reversed it. Other researchers said it was an "exciting finding".
Ageing is considered a one-way street, but now researchers at Harvard Medical School have shown that some aspects can be reversed. Their research focused on a chemical called NAD. Its levels naturally drop in all cells of the body with age. The team showed this damaged the function of the cell's in-built power-stations, leading to lower energy production and ageing.
Experiments showed that increasing NAD levels, by giving mice a chemical which they naturally change into NAD, could reverse the sands of time. One week of youth-medication in two-year-old mice meant their muscles became similar to those of a six-month-old .
Dr Ana Gomes, from the department of genetics at Harvard Medical School, said: "We believe this is quite an important finding." She argues muscle strength may return with a longer course of treatment. However, this could never be a cure-all for ageing. Other aspects such as shortening of telomeres or damage to DNA would not be reversed.
Dr Gomes told the BBC: "Ageing is multi-factorial, it's not just one component（成分） we can fix, so it's hard to target the whole thing. I believe there is a lot of cross-talk in cells and energy is very important in a cell and likely to be a very big component of ageing that might cause some of the other things that happen with ageing."
68. From paragraph 1 we learn that ________.
A. bones can be transformed
B. muscle strength can be transformed
C. color can be transformed
D. muscle can be transformed
69. From paragraph 2 and paragraph 3 we learn that
A. researchers think ageing is a one-way street.
B. NAD levels’ dropping could make mice become younger.
C. increasing NAD levels could make mice become younger.
D. researchers think any aspect can be reversed.
70. Dr Gomes will agree that
A. we can target everything about ageing.
B. muscle strength may return over a longer course of treatment.
C. ageing could be cured.
D. energy is of little importance in a cell.
期末宝典单元检测分类复习卷系列答案科目：高中英语 来源： 题型：阅读理解
Fear can be fun. Many young people queue up to ride very fast and scary roller coasters, screaming but enjoying themselves. Other people like to read “goose bumps (鸡皮疙瘩)” books or watch horror movies at night, scared to death but feeling excited. Why do people like being scared?
Fear is an ancient way of surviving. Being scared makes animals, including humans escape from danger and save themselves. It is because of fear that we have lived through millions of years of evolution. Those who lacked a strong fear response were more likely to be killed, leaving the more fearful and careful to pass their genes onto the next generation.
How do scientists explain why shaking over such scary things is fun? “Some kids will go to a scary movie and love it and laugh over it, others will feel anxious and hide their faces and some won’t even set foot in the cinema,” said Ned Kalin, a US scientist. “Which kind of person you are depends partly on experiences you’ve had and partly on your genes.”
What happens in the brain when something frightens you? Nerves that begin at the eyes and ears lead to a part of the brain called the amygdale. When you suddenly see a snake, for example, the amygdale makes you freeze, sweat, have a quickened heartbeat, or run very fast. However, seeing the snake also uses another part of the brain, the cortex. It analyzes the situation, and if it finds that the snake is only made of rubber it tells your heart and the rest of your body to calm down. Think of the amygdale as the engine and the cortex as the brake.
Back to the first question: Why do some people like to make themselves scared? “One reason is that we can play games with fear, find ways to reduce the scariness by looking away or thinking of something else,” Kalin said. “To believe we have control over a situation gives us a feeling of power.” “Scary movies or novels are good practice to prepare young people for the real thing. Thrills such as roller coaster rides also go to the brain’s pleasure centre.”
And there might be some evolutionary advantage to being able to adjust this system that is there to protect people.
72. How many questions are answered in the passage?
A. 2. B. 3. C. 4. D. 5.
73. Some people like to be scared because______.
A. they are afraid that the fear genes will be passed onto their children
B. it’s a good practice to get prepared for the real frightening situation
C. it can help them show their own personalities
D. they will feel powerful after getting rid of fear
74. Which of the following is true about the people who are not easily scared?
A. Their cortex is better at analyzing the situations.
B. They are more likely to suffer from potential danger.
C. They are born unaffected by anything horrible.
D. They lack a strong response towards threat.
75. What is the best title of the passage?
A. Ready to scream? B. How to be scared?
C. Willing to shake? D. Why to be scared?
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科目：高中英语 来源：2011-2012学年福建省安溪一中高一下学期期中考试英语试卷（带解析） 题型：阅读理解
Futurologists predict that life will probably be very different in 2050.
TV channels will have disappeared. Instead, people will choose a program from a “menu” and a computer will send the program directly to the television. Today, we can use the World Wide Web to read newspaper stories and see pictures on a computer thousands of kilometers away. By 2050, music, films, programs, newspapers, and books will come to us by computer.
Cars will run on new, clean fuels and they will go very fast. Cars will have computers to control the speed and there won’t be any accidents. Today, many cars have computers that tell drivers exactly where they are. By 2050, the computer will control the car and drive it to your destination. Space planes will take people halfway around the world in 2 hours. Today, the United States Space Shuttle can go into space and land on Earth again. By 2050, space planes will fly all over the world and people will fly from Los Angeles to Tokyo in just 2 hours.
Robots will have replaced people in factories. Many factories already use robots. Big companies prefer robots — they don’t ask for pay rises or go on strike, and they work 24 hours a day. By 2050, we will see robots everywhere — in factories, schools, offices, hospitals, shops and homes.
Medical technology will have conquered many diseases. Today, there are devices（设备）that connect directly to the brain to help people hear. By 2050, we will be able to help blind and deaf people to see and hear again.
Scientist will have discovered how to control genes（基因）. Scientists have already produced clones of animals. By 2050, scientists will be able to produce clones of people, and decide how they look, how they behave and how clever they are. Scientists will be able to do these things, but should they?
【小题1】We can learn from the passage that some big companies prefer robots to human workers, because human workers __________.
| A．often ask for more pay |
| B．can work 24 hours a day |
| C．are not clever enough |
| D．are often late for work |
| A．discovered | B．treated | C．caused | D．cured |
| A．few diseases will attack people by 2050 |
| B．there will be no blind and deaf people by 2050 |
| C．medical technology will be more effective by 2050 |
| D．devices are connected directly to the brain to help people hear |
| A．The author does not support the use of cloning technology. |
| B．The author thinks human cloning is impossible. |
| C．The author does not really support the idea of human cloning. |
| D．The author is quite excited about human cloning. |
| A．Read newspapers on a computer. |
| B．Make a space shuttle to go into the land. |
| C．Use computers to control car speed. |
| D．Choose TV programs freely from a “menu”. |
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科目：高中英语 来源：2012-2013学年浙江省台州市书生中学高二下学期期中考试英语试卷（带解析） 题型：阅读理解
Scientists have proved that sleeping and learning go hand in hand. Even a short nap can boost our memory and sharpen our thinking. But the relationship goes deeper than that.
“The brain is not passive while you sleep,” scientist Anat Arzi said. “It’s quite active. You can do many things while you are asleep.”
Arzi and her coworkers didn’t try to teach the sleeping volunteers any complex information, like new words or facts. Instead, the scientists taught volunteers to make new connections between smells and sounds.
When we smell something good, like a flower, we take deep breaths. When we smell something bad, we take short breaths. Arzi and her co-workers based their experiment on these reactions.
Once the volunteers fell asleep in the lab, the scientists went to work. They gave them a whiff of something pleasant and meanwhile played a particular musical note. They didn’t wake up, but they heard—and sniffed(吸气) deeply. Then the scientists gave the volunteers a whiff of something terrible and played a different musical note. Again, the volunteers heard and smelled—a short snort this
time—but didn’t wake up. The researchers repeated the experiment.
After just four repetitions, volunteers made a connection between the musical notes and their paired smells. When the scientists played the musical tone that went with good smells, the sleepers breathed deeply. And when the scientists played the musical tone that went with bad smells, the sleepers breathed briefly—despite there being no bad smell.
The next day, the volunteers woke up with the sound-smell connection. They breathed deeply when hearing one tone and cut their breaths short when hearing the other, which must have been unusual for them. Imagine walking down the street and taking a deep breath upon hearing a particular sound!
【小题1】In the study, the volunteers were taught _______.
| A．to become active during sleep |
| B．to tell the difference between smell |
| C．to learn new words and scientific facts |
| D．to make sound-smell connections |
| A．They took a deep breath. | B．They had a wonderful dream. |
| C．They woke up at once. | D．They took a short breath. |
| A．learned how to play to musical tones |
| B．forgot what happened during their sleep |
| C．continued with the sound-smell connection |
| D．changed their reaction when hearing. |
| A．special smells and sounds can improve our memory. |
| B．our brain can actually learn something new during the sleep. |
| C．the volunteers will always hear similar sounds in the street. |
| D．our brain can tell the difference between smells during the sleep. |
| A．A short sleep can improve our memory and sharpen our thinking. |
| B．Arzi and her coworkers didn’t try to teach the sleeping volunteer some simple information. |
| C．When the volunteer smelt something terrible, they didn’t wake up. |
| D．After four repetitions, volunteers made a connection between the musical notes and their pared smells. |
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科目：高中英语 来源：2014届河北衡水第十四中学高二下学期期末考试英语卷（解析版） 题型：阅读理解
How could we have thought so wrongly of as banana peel that it always hits the garbage? Utility of anything seems to be in the eyes of the beholder. The banana peel hasn't been an exception.
What most of us looked at as waste was converted to a thing of utility by Prithwis Mukhopadlyay, a 14-year-old prodigy. This Bengali boy, nourished in the US, Lake Junior High in Woodbury, Minnesota, has come up with an idea to convert banana peels to biogas.(生物气).
It's well known that almost any organic waste can be converted to biogas. But why biogas from banana peel has hit the news is because it produced five times as much biogas as manure(粪), a commonly used source for producing biogas, in the experiments Prithwis conducted.
He filled two airtight containers, one with manure and the other with banana peels. Then he mixed each content with water and connected them to empty jars via pipes to collect the gas produced. He placed a heater next to each jar and measured the gas collected for 60 days. His studies proved that banana peels produced five times more biogas than manure.
This project titled 'Comparison analysis: Eco-friendly source of energy for the future,' earned him a spot in Discovery Channel Young Scientist Challenge. This weekend, the young whiz is to showcase his research work along with 40 other finalists at Washington. "Initially, I thought of doing a project that would reduce global warming. Things changed after I visited a biogas plant in a village in India during my summer vacations. It was an amazing experience," Prithwis says.
1.Why could Prithwis's finding receive the attention of the media?
A．Because he is a prodigy.
B．Because he is of Bengali descent.
C．Because he used an extremely rare organic waste to produce biogas.
D．Because his research proved that banana peels can produce more biogas.
2.Where did Prithwis derive his inspiration from?
A.Lake Junior High. B Discovery Channel.
C. India. D.His laboratory at home.
3.This article probably appeared in a _________ magazine.
A．gourmet B．science C．computer D．fashion
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科目：高中英语 来源：江苏期末题 题型：阅读理解
| 任务型阅读。 | |
| Vegetables may aid the brain A study suggests certain vegetables such as broccoli(西兰花)and spinach(菠菜)might help older women keep their minds sharp. Researchers have discovered that women in their 60s who eat more green leafy vegetables how less signs of mental decline over time, reported Wednesday's CRI online. They gave participants a bundle of tests measuring memory, oral ability and attention. The study didn't include men, but researchers say a similar diet would likely have the same results. Eating fish can cut risk of heart rhythm disorder US scientists have found that eating fish can reduce the risk of deadly heartbeat disorders. They say baked fish can effectively reduce the risk of atria fibrillation(心房颤动)among older men and women, reported Tuesday's CRI online. Researchers say in their 12 years of research among 4,800 people over the age of 65, they found those who ate fish one to four times per week had an about 30 percent lower risk compared with those who ate fish less than once a month. They say the omega-3 fatty acid can reduce the risk of a range of heart disorders and is vital to brain development and function. Red wine may extend life US scientist have found that a mixture that makes red wine a healthy drink may also hold the secret to a longer life. They say antioxidant(抗氧化剂) in wine acted on fruited flies and worms in the same way as a method known to extend the life of many animals, which is by sharply limiting how much they eat. Limiting calories has been shown to make animals such as dogs and monkeys live longer, but they are often tired and lose productivity. The researchers will begin testing the mixture in mice. | |
 |
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