单选题{{B}}第三篇{{/B}} {{B}} More About Alzheimer's Disease{{/B}} Scientists have developed skin tests that may be used in the future to identify people with Alzheimer's disease and may ultimately allow physicians to predict who is at risk of getting this neurological disorder. The only current means of diagnosing the disease in a living patient is a long and expensive series of tests that eliminate every other cause of dementia. "Since Alois Alzheimer described the disease nearly a century ago, people have been trying to find a way to accurately diagnose it in its early stages," said Patricia Grady, acting director of the National Institute of Neurological Disorders and Stroke in Bethesda, Maryland. "This discovery, if confirmed, could prove a big step forward in our efforts to deal with and understand the disease." Alzheimer's is the single greatest cause of mental deterioration in older people, affecting between 2.5 million and 4 million people in the United States alone. The devastating disorder gradually destroys memory and the ability to function, and eventually causes death. There is currently no known treatment for the disease. Researches discovered that the skin cells of Alzheimer's patients have defects that interfere with their ability to regulate the flow of potassium in and out of the cells. The fact that the cell defects are present in the skin suggests that Alzheimer's results from physiological changes throughout the body, and that dementia may be the first noticeable effect of these changes as the defects affect the cells in the brain, scientists said. The flow of potassium is especially critical in cells responsible for memory formation. The scientists also found two other defects that affect the cells' supply of calcium, another critical element. One test developed by researchers calls for growing skin cells in a laboratory culture and then testing them with an electrical detector to determine if the microscopic tunnels that govern the flow of potassium are open. Open potassium channels create a unique electrical signature. A spokesman for the Alzheimer's association said that if the validity of the diagnostic test can be proven it would be important development, but cautioned that other promising tests for Alzheimer's have been disappointing.

单选题Birds are abundant in the tall vegetation.

单选题We have taken effective measures to preserve our natural resources.

单选题There seemed to be no motive for the murder.

单选题Is the Tie a Necessity? Ties, or neckties, have been a symbol of politeness and elegance in Britain for centuries. But the casual Prime Minister Tony Blair has problems with them. Reports suggest that even the civil servants may stop wearing ties. So, are the famously formal British really going to abandon the neckties? Maybe. Last week, the UK's Cabinet Secretary Andrew Turnbull openly welcomed a tieless era. He hinted that civil servants would soon be free of the costliest 12 inches of fabric that most men ever buy in their lives. In fact, Blair showed this attitude when he had his first guests to a cocktail party. Many of them were celebrities (知名人士) without ties, which would have been unimaginable even in the recent past. For some more conservative British, the tie is a must for proper appearance. Earlier, Labor leader Jim Callaghan said he would have died rather than have his children seen in public without a tie. For people like Callaghan, the tie was a sign of being complete, of showing respect. Men were supposed to wear a tie when going to church, to work in the office, to a party - almost every social occasion. But today, people have begun to accept a casual style even for formal occasions. The origin of the tie is tricky. It started as something called simply a "band". The term could mean anything around a man's neck. It appeared in finer ways in the 1630s. Frenchmen showed a love of this particular fashion statement. Their neckwear (颈饰) impressed Charles II, the king of England who was exiled (流放) to France at that time. When he returned to England in 1660, he brought this new fashion item along with him. It wasn't, however, until the late 18th century that fancy young men introduced a more colorful, flowing piece of cloth that eventually became known as the tie. Then, clubs, military institutions and schools began to use colored and patterned ties to indicate the wearer's membership in the late 19th century. After that, the tie became a necessary item of clothing for British gentlemen. But now, even gentlemen are getting tired of ties. Anyway, the day feels a bit easier when you wake up without having to decide which tie suits you and your mood.

单选题The test produced disappointing results.

单选题Human Heart Can Make New Cells Solving a longstanding mystery, scientists have found that the human heart continues to generate new cardiac cells throughout the life span, although the rate of new cell production slows with age. The finding, published in the April 3 issue of Science, could open a new path for the treatment of heart diseases such as heart failure and heart attack, experts say. "We find that the beating cells in the heart, cardiomyocytes, are renewed," said lead researcher Dr. Jonas Frisen, a professor of stem cell research at the Karolinska Institute in Stockholm, Sweden. "It has previously not been known whether we were limited to the cardiomyocytes we are born with or if they could be renewed," he said. The process of renewing these ceils changes over time, Frisen added. In a 20-year-old, about 1 percent of cardiomyocytes are exchanged each year, but the turnover rate decreases with age to only 0.45 percent by age 75. "If we can understand how the generation of new cardiomyocytes is regulated, it may potentially possible to develop pharmaceuticals that promote this process to stimulate regeneration after, for example, a heart attack," Frisen said. That could lead to treatment that helps restore damaged hearts. "A lot of people suffer from chronic heart failure," noted co-author Dr. Ratan Bhardwaj, also from the Karolinska Institute. "Chronic heart failure arises from heart cells dying," he said. With this finding, scientists are "opening the door to potential therapies to having ourselves heal ourselves," Bhardwaj said. "Maybe one could devise a pharmaceutical agent that would make heart cells make new and more cells to overcome the problem they are facing." But barriers remain. According to Bhardwaj, scientists do not yet know how to increase heart cell production to a rate that would replace cells faster than they are dying off, especially in older patients with heart failure. In addition, the number of new cells the heart produces was estimated using healthy hearts--whether the rate of cell turnover in diseased hearts is the same remains unknown.

单选题The dentist has decided to take out the girl"s bad tooth.

单选题If wool is put into hot water, it tends to shrink .

单选题The high speed trains can have a major impact on our lives.

单选题A red flag was placed there as a {{U}}token{{/U}} of danger. A. sign B. substitute C. proof D. target

单选题 阅读下面的短文，文中有15处空白，每处空白给出了4个选项，请根据短文的内容从 4个选项中选择1个最佳答案。 {{B}}The Great Newspaper War{{/B}} Up until about 100 years ago, newspapers in the United States appealed only to the most serious readers. They used no illustrations and the articles were{{U}} (51) {{/U}}politics or business. Two men{{U}} (52) {{/U}}that -- Joseph Pulitzer of the New York World and William Randolph Hearst of the New York Morning Journal. Pulitzer{{U}} (53) {{/U}}the New York World in 1883. He changed it from a traditional newspaper into a very {{U}} (54) {{/U}}one overnight (一夜之间). He{{U}} (55) {{/U}}lots of illustrations and cartoons. And he told his reporters to write articles on{{U}} (56) {{/U}}crime or scandal they could find. And they did. One of them even pretended she was crazy and then she was{{U}} (57) {{/U}}to a mental hospital. She then wrote a series of articles about the poor{{U}} (58) {{/U}}of patients in those hospitals. In 1895, Hearst{{U}} (59) {{/U}}to New York from California. He wanted the New York Morning Journal to be more sensational (轰动的) and more exciting{{U}} (60) {{/U}}the New York World. He also wanted it to be cheaper, so he{{U}} (61) {{/U}}the price by a penny. Hearst attracted attention because his headlines were bigger than{{U}} (62) {{/U}}. He often said, "Big print makes big news." Pulitzer and Hearst did anything they{{U}} (63) {{/U}}to sell newspapers. For example, Hearst sent Frederic Remington, the famous illustrator (插图画家), to{{U}} (64) {{/U}}pictures of the Spanish-American War. When he got there, he told Hearst that no fighting was{{U}} (65) {{/U}}. Hearst answered, "You furnish (提供) the pictures. I'll furnish the war."

单选题Alexander's parents were supportive, and checked him into an addiction treatment center in Eastern Washington. But his fellow patients at the center were battling alcoholism, heroin addiction and other serious substance abuse problems - issues Alexander couldn't relate to. " It wasn't really working for me, "he says. He left the center to try a wilderness adventure program in the Utah desert (which didn't help either), until his parents discovered RESTART, where, for $ 24,500 (including application, screening and treatment fees), "guests" could spend 45 days cut off from the computer, integrated into a real family's home with chores, daily counseling sessions and weekly therapy. From the paragraph we can infer that Alexander did well inA. the addiction treatment center in Eastern Washington.B. the wilderness adventure program in the Utah desert.C. the Internet and video - game addiction center RESTART.D. a hospital - based addiction treatment center.

单选题Happiness A proverb allegedly (据说) from ancient China was widely spread in the West: "If you want to be happy for a few hours, go to get drunk; if you want the happiness to last three years, get married; if you want a lifetime happiness, take up gardening." The reason for the last option is this: Gardening is not only useful; it helps you to identify yourself with nature, and thus brings you new joy each day besides improving your health. A research of a US university that I"ve read gives a definition of happiness as what makes a person feel comfortably pleased. To put it specifically, happiness is an active state of mind where one thinks one"s life is meaningful, satisfactory and comfortable. This should be something lasting rather than transitory. Lots of people regard it the happiest to be at leisure. But according to the study, it is not a person with plenty of leisure but one at work that feels happy, especially those busy with work having little time for leisure. Happiness does not spell gains one is after but a desire to harvest what one is seeking for. People often do not cherish what they already have but yearn for what they cannot get. That is somewhat like a man indulging in dreams of numerous lovers while reluctant to settle down with the woman beside him. Happiness is a game balancing between two ends—what one has and what one wishes for, i.e., one"s dream and the possibility to realize it. The study comes to this conclusion: A happy man is one who aims high but never forgets his actual situation; one who meets challenges that tap his ability and potentiality; one who is proud of his achievements and the recognition given to him. He has self-respect and self-confidence; treasures his own identity and loves freedom. He is sociable and enjoys wide-range communication with others; he is helpful and ready to accept assistance. He knows he is able to endure sufferings and frustrations; he is sensible enough to get fun from daily chores. He is a man capable of love and passion.

单选题Many scientists have been Uprobing/U psychological problems.

单选题He said some {{U}}harsh{{/U}} words about his brother. A. proper B. normal C. unkind D. unclear

单选题Step Back in Time Do you know that we live a lot longer now than the people who were born before us? One hundred years ago the average woman lived to be 45. But now, she can live until at least 80. One of the main reasons for people living longer is that we know how to look after ourselves better. We know which foods are good for us and what we have to eat to make sure our bodies get all the healthy things they need. We know why we sometimes get ill and what to do to get better again. And we know how important it is to do lots of exercise to keep our hearts beating healthily. But in order that we don"t slip back into bad habits, let"s have a look at what life was like 100 years ago. Families had between 15 and 20 children, although many babies didn"t live long. Children suffered from lots of diseases, especially rickets(佝偻病) and scurvy (坏血病), which are both caused by bad diets. This is because many families were very poor and not able to feed their children well. Really poor families who lived in crowded cities like London and Manchester often slept standing up, bending over a piece of string, because there was no room for them to lie down. People didn"t have fridges until the 1920s. They kept fresh food cold by storing it on windowsills(窗台板), blocks of ice, or even burying it in the garden. Some children had to start work at the age of seven or eight to earn money for their parents. If you had lived 100 years ago, you might well be selling matchsticks(火柴杆) (a job done by many children) or working with your dad by now.

单选题He {{U}}purchased{{/U}} a ticket and went up on the top deck.

单选题When did British gentlemen begin to wear ties regularly?

单选题The world is known to us through many senses, not just hearing, smell, vision, and at close range, touch and taste. Our skins let us know whether the air is moist or dry, whether surfaces are wet without being sticky or slippery. From the uniformity of slight pressure, we can be aware how deeply a finger is thrust into water at body temperature, even if the finger is enclosed in a rubber glove that keeps the skin completely dry. Many other animals, with highly sensitive skins, appear to be able to learn still more about their environment. Often they do so without employing any of the five senses. By observing the capabilities of other members of the animal kingdom, we come to realize that a human being has far more possibilities than are utilized. We neglect ever so many of our senses in concentrating on the five major ones. At the same time, a comparison between animals and man draws attention to the limitations of each sense. The part of the spectrum(光谱)seen by color-conscious man as red is non-existent for honey-bees. But a bee can see far more in flowers than we, because the ultra-violet(紫外线)to which our eyes are blind is a stimulating(刺激的)part of the insect's spectrum, and, for honeybees at least, constitutes a separate color.