题目内容
The Greatest Mystery Of Whales The whale is a warm-blooded, air-breathing animal, giving birth to its young alive, sucking them—and, like all mammals, originated on land. There are many front flippers (鳍状肢), used for steering and stability, are traces of feet. 1 of this. Its Immense strength is 2 into the great body of the big whales, and in fact most of a whale’s body is one gigantic muscle. The blue whale’s pulling strength has been estimated 3 400 horsepower. One specimen was reported to have towed (拖) a whaling vessel for seven hours at the 4 of eight knot (节). An angry whale will 5 A famous example of this was the fate of Whaler Essex, 6 was sunk off the coast of South America early in the last century. More recently, steel ships have 7 their plates buckled (使弯曲) in the same way. Sperm whales (抹香鲸) were known to seize the old-time whaleboats in their jaws and crush them. The greatest 8 of whales is their diving ability. The sperm whale dives to the Bottom for his 9 food, the octopus (章鱼). In that search he is known to go as far Down as 3200 feet, where the. 10 is 1400 pounds, to a square inch. Doing so he will 11 underwater long as one hour. Two special skills are involved in this storing up enough 12 (all whales are air—breathed) and tolerating the great change in pressure. Just how he does it scientists have not 13 . It is believed that some of the oxygen is stored in a special 14 of blood vessels, rather than just held in the lungs. And it is believed that a special kind of oil in his head is some sort of compensating mechanism that 15 adjusts the internal pressure of his body. But since you can’t bring a live whale into the laboratory for study, no one knows just how these things work.
查看答案
搜索结果不匹配？点我反馈
更多问题
The Body Thieves In the early nineteenth century in Britain, many improvements were being made in the world of medicine. Doctors and Surgeons were becoming more knowledgeable about the human body. Illnesses that had been fatal a few years before were now curable. However, Surgeons had one problem. They needed dead bodies to cut up, or dissect (解剖). This was the only way that they could learn about the flesh and bones inside the body, and the only way to teach new surgeons to carry out operations. The job of finding these dead bodies was carried out by an unpleasant group of people called "body snatchers". They went into graveyards (墓地) at night and, using wooden shovels to make less noise, dug up any recently buried bodies. Then they took the bodies to the medical schools and sold them. A body could be sold for between ￡5 and 10, which was a lot of money at that time. The doctors who paid the body snatchers had all agreement with them—they never asked any questions. They did not desire to know where the bodies came from, as long as they kept arriving. The most famous of these body snatchers were two men from Edinburgh called William Burke and William Hare. Burke and Hare were different because they did not just dig up bodies from graveyards. They got greedy and thought of all easier way to find bodies. Instead of digging them up, they killed the poorer guests in Hare’s small hotel. Dr. Knox, the respected surgeon they worked for, never asked why all the bodies they brought him had been strangled (勒死). For many years Burke and Hare were not caught because, unsurprisingly, the bodies of their victims were never found by the police. They were eventually arrested and put on trial in 1829. The judge showed mercy to Hare and he was released but Burke Was found guilty and his punishment was to be hanged. Appropriately, his body Was given to the medical school and he ended up on the dissecting table, just like his victims. In one small way, justice was done. Now, over 150 years later, surgeons do not need the help of criminals to learn their skills. However, the science of surgery could not have developed without their rather gruesome (令人毛骨悚然的) help. The problem facing British surgeons in the early 19th century was that ______.
Eat More, Weigh Less, Live Longer Clever genetic detective work may have found out the reason why a near starvation diet prolongs the life of many animals. Ronald Kahn at Harvard Medical School in Boston, US, and his colleagues have been able to extend the lifespan (寿命) of mice by 18 per cent by blocking the rodent’s (啮齿动物) increase of fat in specific cells. This suggests that thinness—and hot necessarily diet—promotes long life in "calorie (热量卡) restricted" animals. "It’s very cool work." says aging researcher Cynthia Kenyon of the University of California, San Francisco. "These mice eat all they want, lose weight and live longer. It’s like heaven." Calorie restriction dramatically extends the lifespan of organisms as different as worms and rodents. Whether this works in humans is still unknown, partly because few people are willing to submit to such a strict diet. But many researchers hope they will be able to trigger the same effect with a drug once they understand how less food leads to a longer life. One theory is that eating less reduces the increase of harmful things that can damage cells. But Kahn’s team wondered whether the animals simply benefit by becoming thin. To find out, they used biology tricks to disrupt the insulin (胰岛素) receptor (受体) gene in lab mice—but only in their fat cells. "Since insulin is needed to help fat cells store fat, these animals were protected against becoming fat," explains Kahn. This slight genetic change in a single tissue had dramatic effects. By three months of age, Kahn, those modified mice had up to 70 per cent less body fat than normal control mice, despite the fact that they ate 55 per cent more food per gram of body weight. In addition, their lifespan increased. The average control mouse lived 753 days, while the thin rodents averaged a lifespan of 887 days. After three years, all the control mice had died, but one—quarter of the modified rodents were still alive. "That they get these effects by just manipulating the fat cells is controversial," says Leonard Guarente of the Massachusetts Institute of Technology, who studies calorie restriction and aging. But Guarente says Kahn has yet to prove that the same effect is responsible for increased lifespan in calorie, restricted animals. "It might be the same effect or there might be two routes to long life," he points out, "and that would be very interesting." What can be inferred from the passage about the route to long life
Smoke Gets in Your Mind 1. Lung cancer, hypertension, heart disease, birth defects-we are all too familiar with the dangers of smoking. But add to that list a frightening new concern. Mental illness. According to some controversial new findings, if smoking does not kill you, it may, quite litter, drive you to despair. 2. The tobacco industry openly pushes its product as something to lift your mood and soothe anxiety. But the short-term feel-good effect may mask the truth: that smoking may worsen or even trigger anxiety disorders, panic attacks and depression, perhaps even schizophrenia. 3. Cigarettes and mental illness have always tended to go together. An estimated 1.25 billion people smoke worldwide. Yet people who are depressed or anxious are twice as likely to smoke, and up to 88 per cent of those with psychotic disorders such as schizophrenia smokers. A recent American survey concluded that around half of all cigarettes burn in the fingers of those with mental illness. 4. But the big question is why The usual story is that the illness comes first. Mentally ill people take up smoking, or smoke more to alleviate some of their distress. Even when smoking seems to start before the illness, most doctors believe that early but invisible symptoms of the disorder spark the desire to light up. But perhaps something more sinister is going on. 5. A growing number of researchers claim that smoking is the cause, not the consequence of clinical depression and several forms of anxiety. "We know a lot about the effects of smoking on physical health, and now we are also starting to see the adverse effects in new research on mental illness," says Naomi Breslau, director of research at the Henry Ford Health Care System in Detroit. 6. Breslau was one of the first to consider this heretical possibility. The hint came from studies, published in 1998, which followed a group of just over 1,000 young adults for a five-year period. The 13 per cent who began the study with major depression were around three times more likely to progress from being light smokers to daily smokers during the course of the study, though there was no evidence that depression increased the tendency to take up smoking. But a history of daily smoking before the study commenced roughly doubled the risk of developing major depression during the five-year period Smoking, it seems, could pre-dateillness. 7. At first Breslau concluded that whatever prompts people to smoke might also make them depressed. But as the results of other much larger studies began to back the statistical link, she became more convinced than ever that what she was seeing were signs that smoking, perhaps the nicotine itself, could somehow affect the brain and cause depression. 8. One of these larger studies was led by Goodman, a pediatrician. She followed the health of two groups of teenagers for a year. the first group of 8,704 adolescents were not depressed, and might or might not have been smokers, while the second group of 6,947 were highly depressed and had not been smokers in the past month. After a year her team found that although depressed teenagers were more likely to have become heavy smokers, previous experimentation with smoking was the strongest predictor of such behaviour, not the depression itself. What is more important is that teenagers who started out mentally fit but smoked at least one packet per week during the study were four times more likely to develop depression than their non-smoking peers. Goodman says that depression does not seem to start before cigarette use among teens. "Current cigarette use is however, a powerful determinant of developing high depressive symptoms (症状)." 9. Breslau, too, finds that smokers are as much as four times more likely to have an isolated panic attack and three times more likely to develop longer-term panic disorder than nonsmokers. It’s a hard message to get across, because many smokers say they become anxious when they quit, not when they smoke. But Breslau says that this is a short-lived effect of withdrawal which masks the reality that, in general, smokers have higher anxiety levels than non-smokers or ex-smokers. A. Doubt about the Usual Belief B. Researchers’ Opinions Divided C. Positive Effects of Smoking as Advertised D. Close Association Between Depression and Smoking E. Breslau’s Conclusion Supported by Another Larger Study Paragraph 3 ______
American Sports The United States is a sports-loving nation. Sports in America take a variety of forms: organized competitive struggles, which draw huge crowds to cheer their favorite team to victory; athletic games, played for recreation anywhere sufficient space is found; and hunting and fishing. Most sports are seasonal, so that what is happening in sports depends upon the time of year. Some sports are called spectator sports, as the number of spectators greatly exceeds the number playing in the game. Baseball is the most popular sport in the US. It is played throughout the spring and summer, and professional baseball teams play well into the fall. Although no other game is exactly like baseball, perhaps the one most nearly like it is the English game of cricket. Football is the most popular sport in the fall. The game originated as a college sport more than 75 years ago. It is still played by almost every college and university in the country, and the football stadiums of some of the largest universities seat as many as 80000 people. The game is not the same as European football or soccer. In American football there are 11 players in each team, and they are dressed in padded uniforms and helmets because the game is rough and injuries are likely to occur. Basketball is the winter sport in American schools and colleges. Like football, basketball originated in the US and is not popular in other countries. Many Americans prefer it to football because it is played indoors throughout the winter and because it is a faster game. It is a very popular game with high schools, and in more than 20 states, state-wide high school matches are held yearly. Other spectator sports include wrestling, boxing, and horse-racing. Although horse-racing fans call themselves sportsmen, the accuracy of the term is questionable, as only the jockeys who ride the horses in the races can be considered athletes. The so-called sportsmen are the spectators, who do "not assemble" primarily to see the horses race, but to bet upon the outcome of each race. Gambling is the attraction of horse racing. Professional baseball teams can continue to play for a long period of time in the fall after the regular baseball seasons of spring and summer.
微信支付 
支付宝支付