单选题He rolled up his trouser leg to exhibit his wounded knee. A. spread B. open C. show D. examine

单选题Smart Exercise Doctors are starting to find more and more information that suggests a connection between exercise and brain development. Judy Cameron, a scientist at Oregon Health and Science University, studies brain development. According to her research, it seems that exercise can make blood vessels, including those in the brain, stronger and more fully developed. Dr. Cameron claims this allows people who exercise to concentrate better. As she says: "While we already know that exercise is good for the heart, exercise can literally cause physical changes in the brain." The effects of exercise on brain development can even be seen in babies. Babies who do activities that require a lot of movement and physical activity show greater brain development than babies who are less physically active. With babies, even a little movement can show big results. Margaret Barnes, a pediatrician (儿科医师), believes in the importance of exercise. She thinks that many learning disabilities that children have in elementary school or high school can be traced back to a lack of movement as babies. "Babies need movement that stimulates their five senses. They need to establish a connection between motion and memory. In this way, as they get older, children will begin to associate physical activity with higher learning, " says Margaret. Older people can beef up their brains as well. Cornell University studied a group of seniors ranging in age from seventy to seventy-nine. Their study showed a short-term memory increase of up to 40 percent after exercising just three hours a week. The exercise does not have to be very difficult, but it does have to increase the heart rate. Also, just like the motion for infants, exercise for older people should involve some complexity. Learning some new skills or motions helps to open up memory paths in the brain that may not have been used for a long time. For most people, any type of physical activity that increases the heart rate is helpful. The main goal is to increase the brain's flow of blood. And your brain can benefit from as little as two to three hours of exercise a week.

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 cells 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 be 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. 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in a laughter clinic, doctors

单选题 Skin Cancer Melanoma (黑素瘤), the deadliest kind of skin cancer is now the most common cancer in {{U}} {{U}} 1 {{/U}} {{/U}}British women, the country's leading cancer organization said Wednesday. Skin cancer has {{U}} {{U}} 2 {{/U}} {{/U}}cervical (子宫颈的) cancer as the top cancer striking women in their 20s, according to the latest data from Cancer Research United Kingdom. The trend is particularly {{U}} {{U}} 3 {{/U}} {{/U}}since younger people are not generally those most susceptible (易患的) to melanoma. Rates of skin cancer are {{U}} {{U}} 4 {{/U}} {{/U}}highest in people over age 75. But experts worry that increasing numbers of younger people being diagnosed with skin cancer could be the {{U}} {{U}} 5 {{/U}} {{/U}}of a dangerous trend. Women in their 20s make {{U}} {{U}} 6 {{/U}} {{/U}}a small percentage of all patients diagnosed with melanoma in Britain, but nearly a third of all cases occur in people younger than 50. Based on current numbers Cancer Research UK predicts that melanoma will become the fourth {{U}} {{U}} 7 {{/U}} {{/U}}common cancer for men and women of all ages by 2024, and that cases will jump from about 90,000 cases a year to more than 15,500. Cancer experts {{U}} {{U}} 8 {{/U}} {{/U}}the rising number of skin cancer cases largely to the surge in people using tanning salons. "Spending time on sun beds is just as {{U}} {{U}} 9 {{/U}} {{/U}}as staying out too long in the sun," said Caroline Cerny of Cancer Research UK. The organization is starting a SunSmart {{U}} {{U}} 10 {{/U}} {{/U}}to warn Britons of the dangers of being too bronzed. "The intensity of ultraviolet rays in some sun beds can be more than 10 {{U}} {{U}} 11 {{/U}} {{/U}}stronger than the midday sun," Cerny said. In the United States, several states require parental approval {{U}} {{U}} 12 {{/U}} {{/U}}minors can use tanning salons. Wisconsin bans people 16 and {{U}} {{U}} 13 {{/U}} {{/U}}from using tanning beds, and others ban children under 14. At least 29 states have regulations governing minors use of tanning salons. In the UK, Scottish politicians passed legislation banning these under 18 from using tanning beds, though it hasn't yet been implemented. There are no plans for {{U}} {{U}} 14 {{/U}} {{/U}}in the rest of the UK. The world Health Organization has previously recommended that tanning beds be regulated because of their potential to damage DNA in the skin. Experts said most deadly skin cancers could be {{U}} {{U}} 15 {{/U}} {{/U}}if people took the proper precautions when in the sun and avoided tanning beds.

单选题 Stomach Ulcer Stomach ulcers are the cause of severe pain for many people. Doctors have been able to help lessen the pain of ulcers, but they could not cure them. Now doctors have discovered a cause of ulcers. This means they may have found a way to cure people who suffer from the stomach pain. Studies show that ten percent of the population will develop an ulcer at some time in their life. So a possible cure is good news for many people. Ulcers are wounds in the stomach that are similar to small cuts or tears. These wounds can harm the tissue in the stomach, the pipe that carries the food to the stomach or parts of the small intestines. Fluids in the stomach then increase the pain of an ulcer. How does a person know he or she has an ulcer? Doctors say most people with ulcers feel a burning pain in their chest or stomach. This pain is often called heart burn. It usually happens before eating or during the night. It causes some people to lose their desire to eat, or they are unable to keep food in their stomachs. Doctors believed that stomach ulcers were caused by unusually strong stomach fluids, which damaged stomach tissue. Now they have discovered that most stomach ulcers are caused by a bacterial organism called Hillico Bactor Pilorie or HPillorie. HPillorie bacteria are what make stomach produce extra stomach fluid. Doctors found that they can kill the bacteria with medicines called antibiotics. Health experts say the discovery of a cure for stomach ulcers can save thousands of millions of dollars in medical costs. They also believe curing stomach ulcers will reduce the number of people who develop stomach cancer. The number of people with stomach cancer is very high in Japan, Southeast Asia and parts of Africa. Doctors say a person is more likely to get an stomach ulcer if his or her family has had one. In fact, a person with the family history of stomach ulcers is three times more likely to get one than other people. There are ways people can protect themselves from developing an stomach ulcer. Doctors say it is more important to reduce the amount of strong fluids in the stomach. To do this, doctors say, people should not smoke cigarettes or drink alcohol. And they say people should reduce tension in their lives.

单选题Which is NOT affected by the number of years we have to live?

单选题Her shoes {{U}}go with{{/U}} her gloves; they look very well together.

单选题Cooking Oil Fumes Cause Tumor The leading cause of lung cancer among women in the city was cooking oil fumes while men are more likely to develop the disease from smoking, said medical experts after a five-year research study. Doctors announced the results yesterday with analysis on some new tendencies in lung cancer. They said patients are younger, especially women. According to the Shanghai Tumor research Institute, more local residents die of lung cancer in the city than anything else. Following breast cancer, it has the second-highest incidence rate. "An unhealthy lifestyle is a very important reason for lung cancer," said Dr He Yumin from Shanghai Minshen Traditional Chinese Medicine Tumor Diagnosis and Treatment Center. He followed 2,276 lung cancer patients for five years. Among them, 1,433 were male. Smoking causes 70 percent of cases among men while only 18 percent of female patients developed cancer from smoking or inhaling second-hand smoke, according to the report. However, more than 60 percent of women with the disease had long term, close contact with strong oil fumes from cooking and complained about irritated eyes and throat. About 32 percent of women fried foods in boiling oil in unventilated kitchens and about 25 percent of women's bedrooms were adjacent to the kitchen. However, local women were surprised to learn cooking oil fumes could lead to cancer. Some claimed they may change food preparation methods. "Unless my family and I don't eat at home every day, I must stay in the kitchen to cook," said Xu Li, a 45-year-old local woman. "I know the fumes are bad for the skin, but it is the first time I heard that it can result in lung cancer. I have already started frying less. " Doctors said women's lung cancer had few links to personal health and physical condition, but was closely related to family cancer history, unhealthy dietary habits and weak immune systems. Other experts agreed with He. "Smoking is by far the biggest cause of lung cancer for men," said Dr Tan Binyong, honorary president of the Respiratory Disease Institute at Fudan University's Medical College. "It's true that second-hand smoke and cooking fumes are the main causes among women. " He's research also warned people not to stand near of stalls selling fried foods due to the poor quality of oils used. The chance of catching lung cancer is three times higher if exposed to the fume for a long time, experts said.

单选题The osprey flies above the water and when it spots a fish it swoops down to catch it.

单选题I Umeant to/U give you this book today, but I forgot.

单选题A dream usually consists of visual images that tell a story.

单选题Rodman met with Tony to try and settle the dispute over his contract. A. solve B. avoid C. mark D. involve

单选题The construction of the railway is said to have been terminated .

单选题It will be full of hazards on the way to success.A. hopesB. dangersC. helpsD. dreams

单选题下面有3篇短文，每篇短文后有5道题。请根据短文回答其后面的问题，为每题确定一个最佳答案。 {{B}}第一篇{{/B}} Irradiated Food Irradiating (照射)fruits, vegetable, pork and chicken to kill insects and bacteria has been approved by the Food and Drug Administration over the past decade or so. Irradiation of other meats, such as beef and lamb, is being reviewed. Federal approval dose not require that industry adopt the process, and few food processors presently offer irradiated products. Market studies have shown that many consumers are afraid that eating irradiated food may cause cancer, despite scientific studied that prove the safety of treated food. Some people argue that more severe government inspection, higher food-safety standards, and more careful food-preparation practices by consumers are all that is needed to ensure that food is safe. Consequently, companies cur rently see no need to spend millions of dollars outfitting(配备) processing plants with the equipment necessary for a process that very few shoppers are in favor of. All supermarkets that sell irradiated food must label that food either directly on the packaging or in the case of bulk items like fruits and vegetables by placing a sign nearby. There is no requirement for the labeling of irradiated food served by chain restaurants or hospitals that buy directly from distributors, nor any regulations for products that contain irradiated ingredients. Presently, the FDA allows food to be treated with types of radiation-gamma rays, high-energy electrons, and X-rays-and sets limits on doses(辐射量) depending on the type of food. The principle is that the does to be used for a certain type of food should not exceed the amount that is sufficient to kill most harmful insects and bacteria present in it. Different types of food, because of their different molecular(分子) compositions, may require different doses of radiation.

单选题The bad news upset me very much.

单选题We packed up the things we had accumulated (积累) over the last three years andA. late B. recentC. final D. past

单选题He is going to compile the data requested by the tax collector.A. sproutB. evadeC. redeemD. gather

单选题The criminal gave us a long chase before we caught him. A. trial B. pursing C. pursuit D. running