1 . Crossing your legs is an extremely common habit; most people don't even notice that they're doing it when they sit down. While you may find it comfortable to sit with one knee crossed over the other, it might be causing health problems that you are not aware of.
A study published in Blood Pressure Monitoring stated that sitting with your legs crossed can increase your blood pressure. The reason for this is that the blood in your legs has to work against gravity to be pumped back to your heart and that crossing one leg over the other increases resistance(阻力), making it even harder for the blood to circulate. This causes your body to increase your blood pressure to push the blood back to the heart. You won't feel any immediate effects, but repeated, drawn-out increases in blood pressure can cause long-term health problems. So, planning to sit for a long period of time? Don't keep your legs crossed.
Crossing your legs at the knee can also cause pressure on the major nerve in your leg that passes just below your knee and along the outside of your leg, explains Richard Graves, a medical expert. This pressure can cause numbness and temporary paralysis (麻痹) of some of the muscles in your foot and leg, preventing you from being able to raise your ankle—what we know as that “pins and needles” sensation. While the feeling of discomfort may only last a minute or two, repeatedly crossing your legs until they feel numb can cause permanent nerve damage.
So next time you sit down, try to get yourself in the habit of sitting with both of your feet on the floor. Not only will it help your posture and stability, but it will also save your health in the long run.
1. What can we learn about crossing one's legs?| A．It is a very bad social habit. |
| B．It is usually practiced on purpose. |
| C．It can do harm to people's health. |
| D．It can make others feel uncomfortable. |
| A．affect your blood pressure |
| B．resist gravity effectively |
| C．lead to heart attacks easily |
| D．improve the function of legs |
| A．slight sharp pains |
| B．being a little nervous |
| C．serious muscle injuries |
| D．being highly flexible |
| A．To compare common habits. |
| B．To give readers some advice. |
| C．To evaluate effects of an experiment. |
| D．To introduce research methods. |
阅读下列短文，从每题所给的四个选项 （A 、B 、C 和 D ）中，选出最佳选项。
Scientists at Harvard University have recycled a kidney(肾)-in a rat. The researchers removed a kidney from a dead rat. Later, the renewed kidney was put into a living rat. It wasn't perfect. It did, however, show signs of working like a kidney should.
"It's really beautiful work," Edward Ross, a kidney researcher at the University of Florida in Gainesville, told Science News. He didn't work on the new study.
Kidneys are bean-shaped and act like guards in the body. They clean the blood by removing waste and extra water. Every day, an adult's kidneys filter (过滤) enough blood to fill a bathtub half full. Along the way, they produce eight cups of urine (尿) from that waste and water. When a person's kidneys fail, all of that waste stays in the body. Such patients can quickly become very sick and die, unless they are regularly connected to a machine that filters their blood.
At any given time, about 100,000 people in the United States are waiting for a replacement kidney. But healthy donated kidneys are difficult to get. Either a living person must donate one, or a kidney must be removed from someone who just died and earlier had agreed to the donation. In either case, people receiving new kidneys face the r isk that their bodies will reject the donated ones.
But there may be another option. Researchers use knowledge of living things to grow or improve tissue that can aid human health. Harald Ott's team at Harvard started with a "used" kidney.
Scientists added kidney cells from rats and blood vessel cells from people to the matrix（母体）. These cells attached themselves and began to multiply. Before long, they formed new kidney tissue.
The scientists placed this renewed kidney into another rat. There it produced a small amount of urine. This experiment shows that the lab-grown kidney can do at least some of the work performed by a healthy kidney.
The results are a promising first step toward helping people with serious kidney problems. "This is still very early, but they've come a long way," Ross said.
1. What can we infer from Paragraph l?
| A．Biology is a new and helpful science. |
| B．It's hard to put the rebuilt kidney into the rat. |
| C．Kidneys are very important to our life. |
| D．A used kidney may be recycled for new life. |
| A．The relationship between kidneys and health. |
| B．The difficulty of curing serious kidney diseases. |
| C．The function and importance of kidneys. |
| D．The methods of curing kidneys diseases. |
| A．To stress used kidneys are hard to get. |
| B．To show the great need for healthy kidneys. |
| C．To explain many American people get kidney diseases. |
| D．To call on people to donate kidneys. |
| A．The scientists are satisfied with the result of the experiment. |
| B．Ross is a kidney expert who is involved in the experiment. |
| C．The function of the renewed kidney is the same as a healthy kidney. |
| D．The renewed kidney produced a great deal of urine. |
If you do not use your arm or your legs for some time, they become weak; when you start using them again, they slowly become strong again. Everybody knows that. Yet many people do not seem to know that memory works in the same way. When someone says that he has a good memory, he really means that he keeps his memory in practice by using it. When someone else says that his memory is poor, he really means that he does not give it enough chance to become strong. If a friend says that his arms and legs are weak, we know that it is his own fault. But if he tells us that he has a poor memory, many of us think that his parents are to blame, and few of us know that it is just his own fault. Have you ever found that some people can’t read or write but usually they have better memories? This is because they cannot read or write and they have to remember things; they cannot write down in a little notebook. They have to remember days, names, songs and stories; so their memory is the whole time being exercised. So if you want to have a good memory, learn from the people: Practice remembering.
1. What is the main reason for one is poor memory? (回答词数不超过8个)2. What will happen if you do not use your arms or legs for some time? (回答词数不超过5个)
3. What is the best title for this passage? (回答词数不超过6个)
4 . We all know what a brain is. A doctor will tell you that the brain is the organ of the body in the head. It controls our body’s functions, movements, emotions and thoughts. But a brain can mean so much more.
A brain can also simply be a smart person. If a person is called brainy, she is smart and intelligent. If a family has many children but one of them is super smart, you could say, “She’s the brains in the family.” And if you are the brains behind something you are responsible for developing or organizing something. For example, Bill Gates is the brains behind Microsoft. Brain trust is a group of experts who give advice. Word experts say the phrase “brain trust” became popular when Franklin D. Roosevelt first ran for president in 1932, Several professors gave him advice on social and political issues facing the U. S.
These professors were called his “brain trust.” These ways we use the word “brain” all make sense. But other ways we use the word are not so easy to understand. For example, to understand the next brain expression, you first need to know the word “drain.” As a verb to drain means to, remove something by letting it flow away. So a brain drain may sound like a disease where the brain flows out the ears. But brain drain is when a country’s most educated people leave their countries to live in another. The brains are, sort of, draining out of the country.
However, if people are responsible for a great idea, you could say they brainstormed it. Here, brainstorm is not an act of weather. It is a process of thinking creatively about a complex topic. For example, business leaders may use brainstorming to create new products, and government leaders may brainstorm to solve problems. If people are brainwashed, it does not mean their brains are nice and clean. To brainwash means to make someone accept new beliefs by using repeated pressure in a forceful or tricky way. Keep in mind that brainwash is never used in a positive way.
1. According to the text, if you’re the CEO of Bai Du you can be called .| A．the brains behind Bai Du | B．Bai Du’s brain trust |
| C．the brain drain of Bai Du | D．the organ of Bai Du |
| A．Because he was smart at giving advice. | B．Because word experts were popular. |
| C．Because he got his brain trust. | D．Because he was the brains behind America. |
| A．Brain trust | B．Brain drain | C．Brainstorm | D．Brainwash |
People who are near-sighted can only see things that are very close to their eyes. Everything else seems blurry. Many people who do a lot of work, such as writing, reading and sewing become near-sighted. People who are far-sighted suffer from just the opposite problem. They can see things that are far away, but they have difficulty in reading a book unless they hold it at arm’s length. If they want to do much reading, they must get glasses, too.
Other people do not see clearly because their eyes are not exactly the right shape. They have what is called astigmatism (散光). This, too, can be corrected by glasses. Some people’s eyes become cloudy because of cataracts (白内障). Long ago these people often became blind. Now, however, it is possible to operate on the cataracts and remove them.
Having two good eyes is important for judging distances. Each eye sees things from a slightly different angle. To prove this to yourself, look at an object out of one eye; then look at the same object out of your other eye. You will find the object’s relation to the background and other things around it has changed. The difference between these two different eye views helps us to judge how far away an object is. People who have only one eye cannot judge distances as people with two eyes.
1. We should take good care of our eyes .
| A．only when we can see well |
| B．only when we cannot see perfectly |
| C．even if we can see well |
| D．only when we realize how important our eyes are |
| A．obvious | B．possible | C．clear | D．unclear |
| A．seeing at night |
| B．seeing objects far away |
| C．looking over a wide area |
| D．judging distances |
| A．one eye bigger than the other |
| B．eyes that are not exactly the right shape |
| C．a difficulty that can be corrected by an operation |
| D．an eye difficulty that cannot be corrected by glasses |
If blood is red, why are veins (静脉) blue?
Actually, veins are not blue at all. They are more of a clear, yellowish color. Although blood looks red when it’s outside the body, when it’s sitting in a vein near the surface of the skin, it’s more of a dark reddish purple color. At the right depth, these blood-filled veins reflect less red light than the surrounding skin, making them look blue by comparison.
Which works harder, your heart or your brain?
That kind of depends on whether you’re busy thinking or busy exercising. Your heart works up to three times harder during exercise, and shifts enough blood over a lifetime to fill a supertanker (超级油轮). But, in the long run, your brain probably tips it, because even when you’re sitting still your brain is using twice as much energy as your heart, and it takes four to five times as much blood to feed it.
Why do teeth fall out, and why don’t they grow back in grown-ups?
Baby (or “milk”) teeth do not last long; they fall out to make bigger room for bigger, stronger adult teeth later on. Adult teeth fall out when they become damaged, decayed (腐烂) and infected by bacteria. Once this second set of teeth has grown in, you’re done. When they’re gone, they are gone. This is because nature figures you’re set for life, and what controls regrowth of your teeth switches off.
Do old people shrink (收缩) as they age?
Yes and no. Many people do get shorter as they age. But, when they do, it isn’t because they’re shrinking all over. They simply lose height as their spine (脊柱) becomes shorter and more curved due to disuse and the effect of gravity (重力). Many (but not all) men and women do lose height as they get older. Men lose an average of 3-4 cm in height as they age, while women may lose 5 cm or more. If you live to be 200 years old, would you keep shrinking till you were, like 60 cm tall, like a little boy again? No, because old people don’t really shrink! It is not that they are growing backwards—their legs, arms and backbones getting shorter. When they do get shorter, it’s because the spine has shortened a little. Or, more often, become more bent and curved.
Why does spinning make you dizzy?
Because your brain gets confused between what you’re seeing and what you’re feeling. The brain senses that you’re spinning using special gravity-and-motion-sensing organs in your inner ear, which work together with your eyes to keep your vision balance stable. But when you suddenly stop spinning the system goes out of control, and your brain thinks you’re moving while you’re not.
Where do feelings and emotions come from?
Mostly from an ancient part of the brain called the limbic system (边缘系统). All mammals have this brain area—from mice to dogs, cats, and humans. So all mammals feel basic emotions like fear, pain and pleasure. But since human feelings also involve other, newer bits of the brain, we feel more complex emotions than any other animal on this planet.
If exercise wears you out, how can it be good for you?
1. What is the color of blood in a vein near the surface of the skin?
| A．Blue. | B．Light yellow. |
| C．Red. | D．Dark reddish purple. |
| A．Because their spine is in active use. |
| B．Because they are more easily affected by gravity. |
| C．Because they keep growing backwards. |
| D．Because their spine becomes more bent. |
| A．In the long run, our brain probably works harder than our heart. |
| B．When our brain senses the spinning, we will feel dizzy. |
| C．The brains of the other mammals are as complex as those of humans. |
| D．Our feelings and emotions come from the most developed area in our brain. |
| A．To give advice on how to stay healthy. |
| B．To provide information about our body. |
| C．To challenge new findings in medical research. |
| D．To report the latest discoveries in medical science. |
7 . Why do men die earlier than women? The latest research makes it known that the reason could be that men's hearts go into rapid decline when they reach middle age.
The largest study of the effects of ageing on the heart has found that women's longevity may be linked to the fact that their hearts do not lose their pumping power with age.
"We have found that the power of the male heart falls by 20--25 percent between 18 and 70 years of age,”said the head of the study, David Goldspink of Liverpool John Moores University in the UK.
"Within the heart there are millions of cells that enable it to beat. Between the age of 20 and 70，one-third of those cells die and are not replaced in men,”said Goldspink. "This is part of the ageing process."
What surprises scientists is that the female heart sees very little loss of these cells. A healthy 70-year-old woman's heart could perform almost as well as a 20-year-old one's.
"This gender difference might just explain why women live longer than men,”said Goldspink.
They studied more than 250 healthy men and women between the ages of 18 and 80，focusing on healthy persons to remove the confusing influence of disease.
The team has yet to find why ageing takes a greater loss on the male heart, said Goldspink.
The good news is that men can improve the health of their heart with regular exercise. Goldspink stressed that women also need regular exercise to prevent their leg muscles becoming smaller and weaker as they age.
1. The underlined word“longevity" in the second paragraph probably refers to ______.| A．health | B．long life | C．ageing | D．effect |
| A．men's heart cells | B．women's ageing process、 |
| C．the gender difference | D．hearts and long life |
| A．women have more cells than men when they are born |
| B．women can replace the cells that enable the heart to beat |
| C．the female heart loses few of the cells with age |
| D．women never lose their pumping power with age |
| A．enable your heart to beat much faster |
| B．find out the reason for ageing |
| C．exercise regularly to keep your heart healthy |
| D．prevent your cells from being lost |
| A．the reason why ageing takes a greater loss on the male heart has been found out |
| B．scientists are on the way to finding out why the male heart loses more of the cells |
| C．the team has done something to prevent the male from suffering the greater loss |
| D．women over 70 could lose more heart cells than those at the age of 20 |
8 . Easy Ways to Keep Your Brain Sharp
Everyone is forgetful, but as we age, we start to feel like our brains are slowing down a bit- -and that can be a very annoying thing.
1.
People who regularly made plans and looked forward to upcoming events had a 50 percent reduced chance of Alzheimer’s disease (早老性痴呆症)，according to a recent study.
2. Go for a walk.
Mildly raised glucose (葡萄糖) levels can harm the area of the brain that helps you form memories and physical activity can help get blood glucose down to normal levels. In fact, exercise produces chemicals that are good for your brain.
3. Learn something new.
Take a Spanish class online, join a drawing club, or learn to play cards. A study found that mental stimulation (刺激) limits the weakening effects of aging on memory and the mind. But the best thing for your brain is when you learn something new and are physically active at the same time.
| A．Focus on the future. |
| B．This can be especially harmful to the aged. |
| C．It should be something like learning gardening. |
| D．So take a few minutes each day to do some reading. |
| E．But don’t worry if your schedule isn’t filled with life changing events. |
| F．Luckily, research shows there is a lot you can do to avoid those moments |
| G．In other words, when you take care of your body, you take care of your brain. |
What do former American president Bill Clinton and rock musician Pete Townshend have in common? Both men have hearing damage from exposure to loud music, and both now wear hearing aids as a consequence. As a teenager, Clinton played saxophone in a band. Townshend, who has the more severe hearing loss, was a guitarist for a band called the Who. He is one of the first rock musicians to call the public's attention to the problem of hearing loss from exposure to loud music.
Temporary hearing loss can happen after only 15 minutes of listening to loud music. One early warning sign is when your ears begin to feel warm while you listen to music at a rock concert or through headphones. One later is that an unusual sound or a ringing is sometimes produced in your head after the concert.
"What happens is that the hair cells in the inner ear are damaged, but they're not dead," says a physician and ear specialist Dr. Sam Levine. According to Dr. Levine, if you avoid further exposure to loud noise, it's possible to recondition the cells somewhat. However, he adds, "Eventually, over a long period of time, hair cells are permanently damaged." And this is no small problem.
What sound level is dangerous? According to Dr. Levine, regular exposure to noise above 85 decibels (分贝) is considered dangerous. The chart below offers a comparison of decibel levels to certain sounds. Here's another measurement you can use. If you're at a rock concert and the music is so loud that you have to shout to make yourself heard, you' re at risk for hearing loss. That's when wearing protective devices such as earplugs becomes critical.
The facts are pretty frightening. But are rock bands turning down the volume? Most aren't. "Rock music is supposed to be loud," says drummer Andrew Sather. "I wouldn't have it any other way. And neither would the real fans of rock. "
Continued exposure to loud music and the failure to wear earplugs can lead to deafness, according to Dr. Levine. He states, "There's no cure for hearing loss. Your ears are trying to tell you something. That ringing is the scream of your hair cells dying. Each time that happens, more and more damage is done. "
| Levels of Common Noises Normal conversation 50 — 65 dB Food blender 88 dB Jet plane flying above a person standing outside 103 dB Rock band during a concert 110 — 140 dB |
1. From Paragraph 1, we can learn that .
| A．loud music is a major cause of hearing loss |
| B．famous people tend to have hearing problems |
| C．teenagers should stay away from school bands |
| D．the problem of hearing damage is widely known |
| A．not to be seen | B．to fill with sound |
| C．to become larger in size | D．to make good again |
| A．a list of harmful sounds |
| B．the effect of rock concerts |
| C．the noise levels of familiar sounds |
| D．relationship between daily activities and hearing loss |
| A．When your ears feel warm, your hair cells are dead. |
| B．Drummer Andrew Sather gives good advice. |
| C．Many are taking the risk of losing hearing. |
| D．Doctors know how to cure hearing loss. |
The breakthrough came after 40 years of research by Professor Geoff Raisman, who found that cells had the possibility to repair damage to nasal (鼻腔的) nerves, the only part of the nervous system that constantly re-grows. “The idea was to take something from an area where the nervous system can repair itself, and does so throughout life, and put it into an area that doesn’t repair itself,” Professor Raisman said.
Polish doctors injected the nasal cells into Mr Fidyka’s spinal cord above and below the injury and used some nerves from his ankle to form a bridge across the damaged tissue. The nasal cells appear to have caused the spinal nerves to repair themselves.
Professor Raisman achieved this with rats in the late 1990s, but this is his greatest success. “I think the moment of discovery for me was Christmas in 1997 when I first saw a rat that couldn’t control its hand put its hand out to me. That was an exciting moment, because I realized then that my belief that the nervous system could be repaired was true.”
Doctors chose the easiest case for their first attempt — it might not work for others. But there is a real sense of hope that an idea once thought impossible has been realized.
David Nicholls, who helped provide money for the breakthrough, said information about the breakthrough would be made available to researchers across the globe.
“What you’ve got to understand is that for three million paralysed people in the world today, the world looks a totally brighter place than it did yesterday,” he said.
1. Why did Professor Geoff Raisman choose cells from the nose?
| A．The nervous system in the nose can repair itself. |
| B．Cells in the nose can be easily transplanted. |
| C．Cells in the nose re-produce rapidly. |
| D．He just wanted to give it a try. |
| A．His study on animals. |
| B．His operation on a paralysed patient. |
| C．His sudden thoughts about Christmas. |
| D．His unusual experience with a sick rat. |
| A．the world is becoming better and brighter |
| B．paralysed people have the hope of recovery |
| C．the report of the breakthrough will be published soon |
| D．researchers across the globe will carry out the operation |
