单选题The boy's death was {{U}}disastrous{{/U}} to him. The poor man never got over from it.

单选题Why did her friends and neighbours stop seeing her after a few months?

单选题We must {{U}}abide by{{/U}} the rules.

单选题 Throughout the world there is a shortage of human organs for transplants. In Britain, for example, 6000 people are waiting for organs ——5000 for kidneys, and the {{U}}(51) {{/U}} for hearts, lungs and livers. {{U}}(52) {{/U}}, only about 1750 kidney, 500 heart and lung, and 650 liver transplants are {{U}}(53) {{/U}} each year. And the waiting {{U}}(54) {{/U}} increases at five percent a year. In the United States only half of the 30000 in need of organs {{U}}(55) {{/U}} them. Hence the great interest in animal-to-human transplants, known as xenografts or xenotransplants (from the Greek work xenos, meaning strange of foreign) {{U}}(56) {{/U}} most scientists believe is the only long-term solution to the organ {{U}}(57) {{/U}}. There have been attempts at xenotransplants {{U}}(58) {{/U}} the beginning of this century but neither has been successful; the longest {{U}}(59) {{/U}} was a 20-day-old baby called Fae, who in 1984 was {{U}}(60) {{/U}} the heart of a baboon. The main {{U}}(61) {{/U}} with any organ transplant is that the immune system of the patient receiving the organ sees the transplant organ {{U}}(62) {{/U}} an invader. The immune system therefore launches a massive attack on the invader, activating enzymes knows as complement, which attack the {{U}}(63) {{/U}} body, eventually killing the patient as well. This rejection has been {{U}}(64) {{/U}} when transplanting human organs between humans by the close matching of tissue and the long-term use of drugs known as immuno-suppressants, first introduced just over ten years ago. With xenotranplants, however, rejection is even more {{U}}(65) {{/U}}; a normal pig's heart, for example, transfuses with human blood can be destroyed in 15 minutes.

单选题Plant Gas Scientists have been studying natural sources of methane for decades but hadn't regarded plants as a producer, notes Frank Keppler, a geochemist at the Max Planck Institute for Nuclear Physics in Heidelberg, Germany. Now Keppler and his colleagues find that plants, from grasses to trees, may also be sources of the greenhouse gas. This is really surprising, because most scientists assumed that methane production requires an oxygen-free environment. Previously, researchers had thought that it was impossible for plants to make significant amounts of the gas. They had assumed that microbes need to be in environments without oxygen to produce methane. Methane is a greenhouse gas, like carbon dioxide. Gases such as methane and carbon dioxide trap heat in Earth's atmosphere and contribute to global warming. In its experiments, Keppler's team used sealed chambers that contained the same concentration of oxygen that Earth's atmosphere has. They measured the amounts of methane that were released by both living plants and dried plant material, such as fallen leaves. With the dried plants, the researchers took measurement at temperatures ranging from 30 degrees Celsius to 70 degrees. At 30 degrees, they found, a gram of dried plant material released up to 3 nanograms of methane per hour. (One nanogram is a billionth of a gram.) With every 10-degree rise in temperature, the amount of methane released each hour roughly doubled. Living plants growing at their normal temperatures released as much as 370 nanograms of methane per gram of plant tissue per hour. Methane emissions tripled when living and dead plant was exposed to sunlight. Because there was plenty of oxygen available, it's unlikely that the types of bacteria that normally make methane were involved. Experiments on plants that were grown in water rather than soil also resulted in methane emissions. That's another strong sign that the gas came from the plants and not soil microbes. The new finding is an "interesting observation," says Jennifer Y. King, a biogeochemist at the University of Minnesota in St. Paul. Because some types of soil microbes consume methane, they may prevent plant-produced methane from reaching the atmosphere. Field tests will be needed to assess the plant's influence, she notes.

单选题He was acquitted on charges of assault with a deadly weapon.

单选题The government would not dare to impose taxes on such necessities as bread or milk.A. cutB. forceC. occurD. charge

单选题Sleep Lets Brain File Memories To sleep. Perchance to file? Findings published online this week by the Proceedings of the National Academy of Science further support the theory that brain organizes and stows memories formed during the day while the rest of the body is catching zzz"s. Gyorgy Buzsaki of Rutgers University and his colleagues analyzed the brain waves of sleeping rats and mice. Specifically, they examined the electrical activity emanating from the somatosensory neocortex (an area that processes sensory information) and the hippocampus, which is a center for learning and memory. The scientists found that oscillations in brain waves from the two regions appear to be intertwined. So-called sleep spindles (bursts of activity from the neocortex) were followed tens of milliseconds later by beats in the hippocampus known as ripples. The team posits that this interplay between the two brain regions is a key step in memory consolidation. A second study, also published online this week by the Proceedings of the National Academy of Sciences, links age-associated memory decline to high glucose level. Previous research had shown that individuals with diabetes suffer from increased memory problems. In the new work, Antonio Convit of New York University School of Medicine and his collaborators studied 30 people whose average age was 69 to investigate whether sugar levels, which tend to increase with age, affect memory in healthy people as well. The scientists administered recall tests, brain scans and glucose tolerance tests, which measure how quickly sugar is absorbed from the blood by the body"s issues. Subjects with the poorest memory recollection, the team discovered, also displayed the poorest glucose tolerance. In addition, their brain scans showed more hippocampus shrinkage than those of subjects better able to absorb blood sugar. "Our study suggests that this impairment may contribute to the memory deficits that occur as people age," Convit says. "And it raises the intriguing possibility that improving glucose tolerance could reverse some age-associated problems in cognition." Exercise and weights control can help keep glucose level in check, so there may be one more reason to go to the gym.

单选题A well-known physician agreed to perform the operation.A. A famousB. An expensiveC. An incompetentD. A talented

单选题Our company employed about one hundred people.A. interviewedB. hiredC. dismissedD. declined

单选题He used to work in a chemical plant, but now he worked in a bank.A. factoryB. forestC. branchD. company

单选题The sailor found it rather difficult to adjust himself to the life on land.A. putB. carryC. liftD. fit

单选题Surprised by a Miracle I had been working in the trauma unit at a local hospital for about a year. You get used to families thinking that a "coma" patient is moving their hand or doing something that they were asked to do. "Following commands" is what we call it. Often it's "wishful thinking" on the Families' Nurses can easily become callous to it. On this particular night during visiting hours, my patient's wife came in. I had taken care of him for several nights. I was very familiar with his care and what he was able to do. Actually, he didn't do anything. He barely moved at all, even when something would obviously hurt him, such as suctioning. His wife was very short, about 5 feet tall. She had to stand on a stool to lean over him, so that she could see his face and talk to him. She climbed up on the stool. I spoke to her for a few minutes, and then stepped out to tend to see my other patients. A few minutes later, she came running out of the room. In an excited voice, she said, "Donna, he's moving his hand!" I immediately thought that it was probably her imagination, and that he had not actually done it on purpose. He had been there about a month at the time and had never made any movements on purpose. I asked her what had happened and she said, "I asked him to squeeze my hand and he did !" This led me to another train of questioning. "But, did he let go when you asked him to?" She said yes, that he had done exactly what she asked. I went into the room with her, not really believing that I would see anything different than I had always seen. But I decided that it would be better to pacify her than to make her think I didn't believe her or that she was somehow mistaken. She asked him to squeeze her hand, which he did. I said, "Well, ask him to let go." He continued to squeeze for a moment, so that when he finally did let go, I really still didn't believe that he had done it on purpose. So, I said, "Ask him to hold up one finger." He did as asked. Well, hmm, this was starting to get my attention. I looked at him, his face still somewhat swollen and his eyes still closed. "Stick out your tongue!" I said. He did it. I almost fell on the floor. It was the first time I had ever seen anyone "wake up".

单选题He inquired whether it was possible to leave his suitcase at the railway station. A. insisted B. suggested C. asked D. called

单选题 下面有3篇短文，每篇短文后有5道题，每道题后面有4个选项。请根据文章的内容，从每题所给的4个选项中选择1个最佳答案。{{B}}第一篇{{/B}} {{B}}First Aid{{/B}} First aid is emergency care for a victim of sudden illness or injury until more skillful medical treatment is available. It may save a life or improve certain vital signs including pulse, temperature, a clear airway (气道), and breathing. In minor emergencies, first aid may prevent a victim's condition from turning worse and provide relief from pain. First aid must be administered as quickly as possible. In the case of the critically injured, a few minutes can make the difference between complete recovery and loss of life. First-aid measures depend upon a victim's needs and the provider's level of knowledge and skill. Knowing what not to do in an emergency is as important as knowing what to do. Improperly moving a person with a neck injury, for example, can lead to permanent spinal (脊柱的) injury and paralysis (瘫痪). Despite the variety of injuries possible, several principles of first aid apply to all emergencies. The first step is to cal*l for professional medical help. The victim, if conscious, should be reassured that medical aid has been requested, and asked for permission to provide any first aid. Next, assess the scene, asking other people or the injured person's family or friends about details of the injury or illness, any care that may have already been given, and preexisting conditions such as diabetes (糖尿病) or heart trouble. The victim should be checked for a medical bracelet (手镯) or card that describes special medical conditions. Unless the accident scene becomes unsafe or the victim may suffer further injury, do not move the victim. First aid requires rapid assessment of victims to determine whether life-threatening conditions exist. One method for evaluating a victim's condition is known by the acronym (首字母缩写语) ABC, which stands for: A - Airway: is it open and clear? B - Breathing: is the person breathing? Look, listen, and feel for breathing. C - Circulation: is there a pulse? Is the person bleeding externally? Check skin color and temperature for additional indications of circulation problems.

单选题Professor Taylor"s talk has indicated that science has a very strong influence on the everyday life of non-scientists as well as scientists.

单选题Keep on Fighting Turning once again to the question of invasion, I would observe that there has never been a period in all these long centuries of which we boast when an absolute guarantee against invasion, still less against serious raids, could have been given to our people. In the days of Napoleon the same wind which would have carried his transports across the Channel might have driven away the blockading (封锁) fleet. There was always the chance, and it is that chance which has excited and befooled (愚弄) the imaginations of many continental tyrants. Many are the tales that are told. We are assured that novel methods will be adopted, and when we see the originality of malice (怨恨), the ingenuity of aggression, which our enemy displays, we may certainly prepare ourselves for every kind of novel stratagem(战略) and every kind of brutal and treacherous (奸诈的) maneuver (花招). I think that no idea is so outlandish (古怪的) that it should not be considered and viewed with a searching, but at the same time, I hope, with a steady eye. We must never forget the solid assurances of sea power and those which belong to air power if it can be locally exercised. I have, myself, full confidence that if all do their duty, if nothing is neglected, and if the best arrangements are made, as they are being made, we shall prove ourselves once again able to defend our island home, to ride out the storm of war, and to outlive the menace (威胁) of tyranny, if necessary for years, if necessary alone. At any rate, that is what we are going to try to do. This is the resolve of his Majesty"s government—every man of them. This is the will of parliament and the nation. The British Empire and the French republic, linked together in their cause and in their need, will defend to the death their native soil, aiding each other like good comrades to the utmost of their strength. Even though large tracts of Europe and many old and famous states have fallen or may fall into the grip of the Gestapo and all the odious (可憎的) apparatus of Nazi rule, we shall not flag (变弱) or fail. We shall go on to the end, we shall fight in France, we shall fight on the seas and oceans, we shall fight with growing confidence and growing strength in the air, we shall defend our island, whatever the cost might be, we shall fight on the beaches, we shall fight on the landing grounds, we shall fight in the fields and in the streets, we shall fight in the hills, we shall never surrender, and even if, which I do not for a moment believe, this island or a large part of it were subjugated (征服) and starving, then our empire beyond the seas, armed and guarded by the British fleet, would carry on the struggle, until, in God"s good time, the new world, with its power and might, steps forth to the rescue and the liberation of the old.

单选题What were the {{U}}effects{{/U}} of the decision she made? A. reasons B. results C. causes D. bases

单选题The witch hazel plants tolerate poor soil, dust and limited sun.A. suffer fromB. survive inC. thrive inD. die from

单选题She shows little regard for the feelings of others and does exactly what she wants to.