单选题 Where Have All the Bees Gone? Scientists who study insects have a real mystery on their hands. All across the country, honeybees are leaving their hives and never returning. Researchers call this phenomenon Colony Collapse Disorder. According to surveys of beekeepers across the country, 25 to 40 percent of the honeybees in the United States have vanished from their hives since last fall. So far, no one can explain why. Colony collapse is a serious concern because bees play an important role in the production of about one-third of the foods we eat. As they feed, honeybees spread pollen from flower to flower. Without this process, a plant can't produce seeds or fruits. Now, a group of scientists and beekeepers have teamed up to try to figure out what's causing the alarming collapse of so many colonies. By sharing their expertise in honeybee behavior, health, and nutrition, team members hope to find out what's contributing to the decline and to prevent bee disappearance in the future. It could be that disease is causing the disappearance of the bees. To explore that possibility, Jay Evans, a researcher at the United States Department of Agriculture (USDA) Bee Research Laboratory, examines bees taken from colonies that are collapsing. "We know what a healthy bee should look like on the inside, and we can look for physical signs of disease," he says. And bees from collapsing colonies don't look very healthy. "Their stomachs are worn down, compared to the stomachs of healthy bees," Evans says. It may be that a parasite is damaging the bees digestive organs. Their immune systems may not be working as they should. Moreover, they have high levels of bacteria inside their bodies. Another cause of Colony Collapse Disorder may be certain chemicals that farmers apply to kill unwanted insects on crops, says Jerry Hayes, chief bee inspector for the Florida Department of Agriculture. Some studies, he says, suggest that a certain type of insecticide affects the honeybee's nervous system (which includes the brain) and memory. "It seems like honeybees are going out and getting confused about where to go and what to do," he says. If it turns out that a disease is contributing to colony collapse, bees, genes could explain why some colonies have collapsed and others have not. In any group of bees there are many different kinds of genes. The more different genes a group has, the higher the group's genetic diversity. So far scientists haven't determined the role of genetic diversity in colony collapse, but it's a promising theory, says Evans.

单选题I want to provide my boys with a decent education.

单选题 The Case of the Disappearing Fingerprints One useful anti-cancer drug can effectively erase the whorls (螺纹) and other characteristic marks that give people their distinctive fingerprints. Losing {{U}} {{U}} 1 {{/U}} {{/U}}could become troublesome. A case released online in a letter by Annals of Oncology indicates how big a {{U}} {{U}} 2 {{/U}} {{/U}}of losing fingerprints is. Eng-HuatTan, a Singapore-based medical doctor describes a 62-year-old man who has used capecitabine to {{U}} {{U}} 3 {{/U}} {{/U}}his nasopharyngeal cancer. After three years on the {{U}} {{U}} 4 {{/U}} {{/U}}, the patient decided to visit U.S. relatives last December. But he was stopped by U.S. Customs officials {{U}} {{U}} 5 {{/U}} {{/U}}4 hours after entering the country when those officials couldn't get fingerprints from the man. There were no distinctive swirly {{U}} {{U}} 6 {{/U}} {{/U}}appearing from his index finger. U.S. Customs has been fingerprinting incoming foreign visitors for years, Tan says. Their index fingers are {{U}} {{U}} 7 {{/U}} {{/U}}and screened against digital files of the fingerprints of bad guys—terrorists and potential criminals that our federal guardians have been tasked with keeping out of the country. Unfortunately, for the Singaporean traveler, one potential {{U}} {{U}} 8 {{/U}} {{/U}}effect of his drug treatment is a smoothing of the tissue on the finger pads. {{U}} {{U}} 9 {{/U}} {{/U}}, no fingerprints. "It is uncertain when fingerprint loss will {{U}} {{U}} 10 {{/U}} {{/U}}to take place in patients who are taking capecitabine," Tan points out. So he cautions any physicians who {{U}} {{U}} 11 {{/U}} {{/U}}the drug to provide their patients with a doctor's note pointing out that their medicine may cause fingerprints to disappear. Eventually, the Singapore traveler made it into the United States. I guess the name on his passport didn't raise any red flags. But he's also now got the explanatory doctor's note—and won't leave home {{U}} {{U}} 12 {{/U}} {{/U}}it. By the way, maybe the Food and Drug Administration, {{U}} {{U}} 13 {{/U}} {{/U}}approved use of the drug 11 years ago, should consider {{U}} {{U}} 14 {{/U}} {{/U}}its list of side effects associated with this medicine. The current list does note that patients may experience vomiting, stomach pain and some other side effects. But no where {{U}} {{U}} 15 {{/U}} {{/U}}it mention the potential for loss of fingerprints.

单选题The city has decided to do away with all the old buildings in its center.

单选题What has happened to aspirin since new painkillers came on the market?

单选题When a person should be considered dead is currently a matter

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}} Be Aware: Teenage Driver A recent study, published in last week's Journal of American Medical Association, offers a picture of how risky it is to get a lift from a teenage driver. Indeed, a 16-year-old driver with three or more passengers is three times as likely to have a fatal accident as a teenager driving alone, by contrast, the risk of death for drivers between 30 and 59 decreases with each additional passenger. The author also found that the death rates for teenager drivers increased dramatically after 10 pm, and especially after midnight. With passengers in the car, the driver was even more likely to die in a late-night accident. Robert Foss, a scientist at the University of North Carolina Highway Stately Research Center, says the higher death rates for teenage drivers have less to do with "really stupid behavior" than with just a lack of driving experience. "The basic issue," he says, "is that adults who are responsible for issuing licenses fail to recognize how complex and skilled a task driving is. " Both he and the author of the study believe that the way to mitigate(使……缓解) the problem is to have states institute so-called graduated licensing systems, in which getting a license is a multistage process. A graduated license requires that a teenager first prove himself capable of driving in the presence of an adult, followed by a period of driving with passenger restrictions, before graduating to full driving privileges. Graduate licensing systems have reduced teenage driver crashes, according to recent studies. About half of the states now have some sort of graduated licensing system in place, but only 10 of those states have restrictions on passengers. California is the strictest, with a novice(新手) driver prohibited from carrying any passenger under 20 ( without the presence of an adult over 25 ) for the first six months.

单选题This poem {{U}}depicts{{/U}} the beautiful scenery of a town in the south.

单选题He"s spent years cultivating knowledge of art.

单选题Theseprogrammes are of immense value to old people.

单选题Be {{U}}suspicious{{/U}} about water from other sources, such as ponds, streams, wells, tanks, water trucks or public standpipes.

单选题The new secretary has written a remarkably concise report only in a few pages but with all the details.

单选题The organization was {{U}}bold{{/U}} enough to face the press. A. pleased B. brave C. powerful D. sensible

单选题We had to abandon the ear and walk the rest of the way.A. give inB. give awayC. give backD. give up

单选题The {{U}}steadily{{/U}} rising cost of labor has greatly increased the cost of shipping cargo by water. A. suddenly B. gradually C. excessively D. exceptionally

单选题He had finished ______ the book and returned it.A. readB. to readC. readingD. reads

单选题She seemed to have detected some anger in his voice.

单选题 Escaping from the Earth The Earth has a force that pulls things toward itself. We call this force gravity(地心引力). This is something we live with all the time, and we take it for granted and hardly ever think about it. But it is a most important factor in rocket operation and must be overcome if we are to get anywhere in space, or off the ground at all. Take the throwing of a ball as an example. The harder the ball is thrown, the faster and higher it will go. What is the secret? Its speed. If we could throw the ball hard enough it would go up and up forever and never come down. The speed at which it would have to be thrown to do this is known as escape speed. Of course, we cannot throw a ball hard enough because the speed required to escape completely from the Earth's gravity is seven miles per second, or over twenty-five thousand miles per hour. Once escape speed has been reached by a spacecraft(宇宙飞船), no further power is needed. A rocket aimed at the Moon, for instance, will "coast"(滑行) the rest of the way because the Earth's gravity cannot then pull it back, and there is no air resistance(阻力) in space to slow it down. This "coasting" is known as "free fall". That does not mean the rocket is falling down towards the Earth but that it is traveling freely in space without the aid of power, like a bicycle coasting downhill. Free fall is an important feature of space travel: it would be impossible to carry enough fuel to provide powered flight all the time.

单选题 Diabetes (糖尿病) and Eye Damage Over 2 million Canadians have diabetes. It is the leading cause of blindness in North Americans under 65 years of age. Diabetes is a condition where the body either cannot produce enough insulin (胰岛素) or cannot respond properly to insulin. Insulin is important because it moves glucose (葡萄糖), a simple sugar, into the body's cells from the blood. The food people eat provides the body with glucose, which is used by the cells as a source of energy. If insulin isn't available or doesn't work correctly to move glucose from the blood into the cells, glucose will stay in the blood, leading to high blood sugar levels. High blood sugar levels damage the blood vessels, including the tiny blood vessels in the eye. This leads to an eye disease known as diabetic retinopathy (糖尿病型视网膜病). The retina (视网膜) is an area at the back of the eye that changes light into nerve signals. With diabetic retinopathy, some blood vessels in the retina are lost, and some of the other blood vessels begin to "leak" blood. This causes the retina to swell, and gradually cuts off its supply of oxygen and nutrients (滋养物). Eventually, the retina starts to grow new blood vessels to replace the damaged ones. Unfortunately, these new vessels are not as strong as the old ones. They are more likely to break, Causing bleeding in the eye. At first, people with diabetic retinopathy will not notice any symptoms. As the disease gets worse, they may notice blurred (模糊的) vision, black spots or flashing lights. As time goes on, it can progress to blindness. Everyone with diabetes is at risk for diabetic retinopathy, and the risk increases the longer you've had diabetes. Fortunately, you can reduce your risk. If you do not have diabetes, but think you may be at risk for this condition, visit your doctor to be screened for diabetes. If you do have diabetes: have frequent eye check-ups. Make sure that you monitor your blood sugar frequently and use your medications as recommended by your doctor. There is evidence to show that keeping your blood sugar under tight control can slow down eye damage. If you have high blood pressure, follow your recommended diet and medications to keep it under control. If you are not sure whether you have high blood pressure, or whether your blood pressure is under control, discuss this with your doctor.

单选题It is difficult to assess the importance of the decision.