单选题 Questions14-16 are based on the passage you have just heard.

单选题In last year's Science study, researchers at Johns Hopkins University examined the relationship between stem-cell divisions and cancer development. They reported that the higher the number of stem-cell divisions in a given tissue, the higher risk for 28 cancer. At the time, they said that their findings suggested '65% of cancer...appears to be explained by the number of stem-cell divisions'. That stem-cell activity, the researchers suggested, could explain why some people without 29 factors like smoking will still get lung cancers. 'I was startled by their conclusion,' Dr. Yusuf Hannun says, a cancer researcher at Stony Brook University in New York and author of the new Nature study. Hannun and his team 30 that the first study assumed that stem-cell division and other environmental factors were 31 of each other. Hannun's team wanted to assess the 32 to which stem-cell division or environmental factors contribute to developing the disease. To do this, the researchers looked at a variety of data including epidemiological evidence that people living in different regions have different rates of cancer development. They also looked at cell-mutation patterns 33 with certain cancers, as well as mathematical models that helped parse how much a cancer was due to 34 factors like cell division versus extrinsic factors like environment or lifestyle. The new study reported that while intrinsic factors did have a 35 in cancer development, environmental factors had a more 36 effect and were responsible for 70%-90% of cancer cases. This isn't the last study to be published on the topic, but as scientists refine their 37 of the many things that can contribute to cancer risk, more information is needed. A. argue B. associated C. considering D. derived E. developing F. extent G. full H. independent I. intrinsic J. relation K. risk L. robust M. role N. seizes O. understanding

单选题 Resilience Is About How You Recharge, Not How You Endure A. As constant travelers and parents of a 2-year-old, we sometimes fantasize about how much work we can do when one of us gets on a plane, undistracted by phones, friends, or movies. We race to get all our ground work done: packing, going through security, doing a last-minute work call, calling each other, then boarding the plane. Then, when we try to have that amazing work session in flight, we get nothing done. Even worse, after refreshing our email or reading the same studies over and over, we are too exhausted when we land to soldier on with (继续处理) the emails that have inevitably still piled up. B. Why should flying deplete us? We're just sitting there doing nothing. Why can't we be tougher, more resilient (有复原力的) and determined in our work so we can accomplish all of the goals we set for ourselves? Based on our current research, we have come to realize that the problem is not our hectic schedule or the plane travel itself; the problem comes from a misconception of what it means to be resilient, and the resulting impact of overworking. C. We often take a militaristic, 'tough' approach to resilience and determination like a Marine pulling himself through the mud, a boxer going one more round, or a football player picking himself up off the ground for one more play. We believe that the longer we tough it out, the tougher we are, and therefore the more successful we will be. However, this entire conception is scientifically inaccurate. D. The very lack of a recovery period is dramatically holding back our collective ability to be resilient and successful. Research has found that there is a direct correlation between lack of recovery and increased incidence of health and safety problems. And lack of recovery—whether by disrupting sleep with thoughts of work or having continuous cognitive arousal by watching our phones—is costing our companies $62 billion a year in lost productivity. E. And just because work stops, it doesn't mean we are recovering. We 'stop' work sometimes at 5pm, but then we spend the night wrestling with solutions to work problems, talking about our work over dinner, and falling asleep thinking about how much work we'll do tomorrow. In a study just released, researchers from Norway found that 7.8% of Norwegians have become workaholics (工作狂). The scientists cite a definition of 'workaholism' as 'being overly concerned about work, driven by an uncontrollable work motivation, and investing so much time and effort in work that it impairs other important life areas.' F. We believe that the number of people who fit that definition includes the majority of American workers, which prompted us to begin a study of workaholism in the U.S. Our study will use a large corporate dataset from a major medical company to examine how technology extends our working hours and thus interferes with necessary cognitive recovery, resulting in huge health care costs and turnover costs for employers. G. The misconception of resilience is often bred from an early age. Parents trying to teach their children resilience might celebrate a high school student staying up until 3am to finish a science fair project. What a distortion of resilience! A resilient child is a well-rested one. When an exhausted student goes to school, he risks hurting everyone on the road with his impaired driving; he doesn't have the cognitive resources to do well on his English test; he has lower serf-control with his friends; and at home, he is moody with his parents. Overwork and exhaustion are the opposite of resilience and the bad habits we acquire when we're young only magnify when we hit the workforce. H. As Jim Loehr and Tony Schwartz have written, if you have too much time in the performance zone, you need more time in the recovery zone, otherwise you risk burnout. Gathering your resources to 'try hard' requires burning energy in order to overcome your currently low arousal level. It also worsens exhaustion. Thus the more imbalanced we become due to overworking, the more value there is in activities that allow us to return to a state of balance. The value of a recovery period rises in proportion to the amount of work required of us. I. So how do we recover and build resilience? Most people assume that if you stop doing a task like answering emails or writing a paper, your brain will naturally recover, so that when you start again later in the day or the next morning, you'll have your energy back. But surely everyone reading this has had times when you lie in bed for hours, unable to fall asleep because your brain is thinking about work. If you lie in bed for eight hours, you may have rested, but you can still feel exhausted the next day. That's because rest and recovery are not the same thing. J. If you're trying to build resilience at work, you need adequate internal and external recovery periods. As researchers Zijlstra, Cropley and Rydstedt write in their 2014 paper: 'Internal recovery refers to the shorter periods of relaxation that take place within the frames of the work day or the work setting in the form of short scheduled or unscheduled breaks, by shifting attention or changing to other work tasks when the mental or physical resources required for the initial task are temporarily depleted or exhausted. External recovery refers to actions that take place outside of work—e.g, in the free time between the work days, and during weekends, holidays or vacations.' If after work you lie around on your bed and get irritated by political commentary on your phone or get stressed thinking about decisions about how to renovate your home, your brain has not received a break from high mental arousal states. Our brains need a rest as much as our bodies do. K. If you really want to build resilience, you can start by strategically stopping. Give yourself the resources to be tough by creating internal and external recovery periods. Amy Blankson describes how to strategically stop during the day by using technology to control overworking. She suggests downloading the Instant or Moment apps to see how many times you turn on your phone each day. You can also use apps like Offtime or Unplugged to create tech free zones by strategically scheduling automatic airplane modes. The average person turns on their phone 150 times every day. If every distraction took only 1 minute, that would account for 2.5 hours a day. L. In addition, you can take a cognitive break every 90 minutes to charge your batteries. Try to not have lunch at your desk, but instead spend time outside or with your friends—not talking about work. Take all of your paid time off, which not only gives you recovery periods, but raises your productivity and likelihood of promotion. M. As for us, we've started using our plane time as a work-free zone, and thus trine to dip into the recovery phase. The results have been fantastic. We are usually tired already by the time we get on a plane, and the crowded space and unstable internet connection make work more challenging Now, instead of swimming upstream, we relax, sleep, watch movies, or listen to music. And when we get off the plane, instead of being depleted, we feel recovered and ready to return to the performance zone.

单选题 端午节(Dragon Boat Festival)，农历五月初五日，已经有2000多年的历史了。赛龙舟(dragon boat racing)在全国各地都举行，是这个节日不可缺少的(indispensable)一部分。当发号枪一响，人们就会看到在龙形的独木舟上，选手们和谐而急速地划桨(oar)，伴随着急促的鼓声，快速朝着目的地划去。据民间故事传说(folk tale)，这一比赛起源于寻找屈原的遗体的活动。现在赛龙舟已经发展成为一个水上运动项目(aquatic sports item)，这是中国的传统与现代体育精神相结合的特征。1980年，赛龙舟被列入国家体育竞赛项目，每年都举办，该奖项被称为“屈原杯”。

单选题 中国传统元素是指被广泛认可的中国传统形象、符号或风俗习惯等。它们能够反映中国传统文化的精髓(essence)，是中国所特有的元素。中国传统元素体现在文学、艺术、建筑、饮食、服饰及风俗习惯等多个方面。从唐诗宋词、京戏脸谱(facial makeup)、雕梁画栋(richly ornamented building)、中餐茶品到唐装刺绣(embroidery)，无不体现着魅力非凡的(charismatic)中国元素。中国传统元素植根于深厚的中国传统文化，它对中国当代及后世的社会发展都有着不可忽视的重要作用，值得我们继续传承下去。

单选题 广告的基本功能即传达信息。如果想告诉某人某件事，你必须引起他的兴趣和注意，这是人际交往、大众传播(mass-communication)中的一个真理。将观众的注意力吸引过来，广告才能实现说服他们相信某个观点的功能。因为名人的知名度，名人广告能轻松地把观众的注意力杂乱的环境中吸引过来，让产品和广告成为大众关注的中心。本来大家并不了解的一个品牌，因为名人的关系随即受到重视，在繁杂的信息中脱颖而出，快速提升产品的知名度。

单选题Research on animal intelligence always makes us wonder just how smart humans are. Consider the fruit-fly experiments described by Carl Zimmer in the Science Times. Fruit flies who were taught to be smarter than the average fruit fly 26 to live shorter lives. This suggests that dimmer bulbs burn longer, that there is a(n) 27 in not being too bright. Intelligence, it turns out, is a high-priced 28 . It takes more upkeep, burns more fuel and is slow off the starting line because it depends on learning—a(n) 29 process—instead of instinct. Plenty of other species are able to learn, and one of the things they've apparently learned is when to stop. Is there an adaptive value to limited intelligence? That's the question behind this new research. Instead of casting a wistful glance 30 at all the species we've left in the dust I.Q.-wise, it implicitly asks what the real costs of our own intelligence might be. This is on the 31 of every animal we've ever met. Research on animal intelligence also makes us wonder what experiments animals would 32 on humans if they had the chance. Every cat with an owner, for instance, is running a small-scale study in operant conditioning. We believe that if animals ran the labs, they would test us to 33 the limits of our patience, our faithfulness, our memory for locations. They would try to decide what intelligence in humans is really for, not 34 how much of it there is. Above all, they would hope to study a 35 question: Are humans actually aware of the world they live in? So far the results are inconclusive. A. mind E. advantage I. aptly M. tended B. fundamental F. happened J. overcome N. inclination C. gradual G. spontaneous K. option O. perform D. determine H. backward L. merely

单选题 Now listen to the following recording and answer questions22-24.

单选题Teachers need to be aware of the emotional, intellectual, and physical changes that young adults experience. And they also need to give serious thought to how they can best 27 such changes. Growing bodies need movement and 28 , but not just in ways that emphasize competition. Because they are adjusting to their new bodies and a whole host of new intellectual and emotional challenges, teenagers are especially serf-conscious and need the confidence that comes from achieving success and knowing that their accomplishments are 29 by others. However, the 30 teenage lifestyle is already filled with so much competition that it would be wise to plan activities in which there are more winners than losers, for example, publishing newsletters with many student-written book reviews, 31 student artwork, and sponsoring book discussion clubs. A variety of small clubs can provide 32 opportunities for leadership, as well as for practice in successful group 33 . Making friends is extremely important to teenagers, and many shy students need the security of some kind of organization with a supportive adult 34 visible in the background. In these activities, it is important to remember that young teens have short attention spans. A variety of activities should be organized so that participants can remain active as long as they want and then go on to something else without feeling 35 and without letting the other participants down. This does not mean that adults must accept irresponsibility. On the contrary, they can help students acquire a sense of 36 by planning for roles that are within their capabilities and their attention spans and by having clearly stated rules. A. dynamics E. displaying I. admired M. accommodate B. multiple F. rarely J. nutrition N. barely C. guidance G. exercise K. commitment O. claimed D. typical H. guilty L. surplus

单选题Go (围棋) is an ancient Asian game. In recent years, computer experts, particularly those 27 in artificial intelligence, have felt the fascination. Programming other board games has been a relative snap. Even chess has 28 to the power of the processor. Five years ago, a chess-playing computer called Deep Blue not only beat but thoroughly 29 Garry Kasparov, the world champion at that time. That is because chess, while highly complex, can be reduced to a matter of brute force computation. Go is different. Deceptively easy to learn, either for a computer or a human, it is a game of such depth and 30 that it can take years for a person to become a strong player. To date, no computer has been able to achieve a skill level beyond that of the casual player. The game is played on a board divided into a grid of 19 31 and 19 vertical lines. Black and white pieces called stones are placed one at a time on the grid's intersections. The object is to acquire and defend 32 by surrounding it with stones. Programmers working on Go see it as more accurate than chess in 33 the ways the human mind works. The challenge of programming a computer to mimic that process goes to the core of artificial intelligence, which involves the study of learning and decision-making, strategic thinking, knowledge representation, pattern recognition and perhaps most intriguingly, intuition. In the 34 of a chess game, a player has an average of 25 to 35 moves available. In Go, on the other hand, a player can choose from an average of 240 moves. A Go-playing computer would need about 30000 years to look as far ahead as Deep Blue can with chess in three seconds. But the 35 go deeper than processing power. Not only do Go programs have trouble evaluating positions quickly; they have trouble making it correctly. 36 , the allure (吸引力) of computer Go increases as the difficulties it poses encourages programmers to advance basic work in artificial intelligence. A. complexity B. Consequently C. course D. horizontal E. humbled F. humiliated G. Nonetheless H. obstacles I. reflecting J. responding K. slanted L. specializing M. submitted N. subscribed O. territory

单选题 Questions2-5 are based on the conversation you have just heard.

单选题 Grow Plants Without Water A. Ever since humanity began to farm our own food, we've faced the unpredictable rain that is both friend and enemy. It comes and goes without much warning, and a field of lush (茂盛的) leafy greens one year can dry up and blow away the next. Food security and fortunes depend on sufficient rain, and nowhere more so than in Africa, where 96% of farmland depends on rain instead of the irrigation common in more developed places. It has consequences: South Africa's ongoing drought—the worst in three decades—will cost at least a quarter of its corn crop this year. B. Biologist Jill Farrant of the University of Cape Town in South Africa says that nature has plenty of answers for people who want to grow crops in places with unpredictable rainfall. She is hard at work finding a way to take traits from rare wild plants that adapt to extreme dry weather and use them in food crops. As the earth's climate changes and rainfall becomes even less predictable in some places, those answers will grow even more valuable. 'The type of farming I'm aiming for is literally so that people can survive as it's going to get more and more dry,' Farrant says. C. Extreme conditions produce extremely tough plants. In the rusty red deserts of South Africa, steep-sided rocky hills called inselbergs rear up from the plains like the bones of the earth. The hills are remnants of an earlier geological era, scraped bare of most soil and exposed to the elements. Yet on these and similar formations in deserts around the world, a few fierce plants have adapted to endure under ever-changing conditions. D. Farrant calls them resurrection plants (复苏植物). During months without water under a harsh sun, they wither, shrink and contract until they look like a pile of dead gray leaves. But rainfall can revive them in a matter of hours. Her time-lapse (间歇性拍摄的) videos of the revivals look like someone playing a tape of the plant's death in reverse. E. The big difference between 'drought-tolerant' plants and these tough plants: metabolism. Many different kinds of plants have developed tactics to weather dry spells. Some plants store reserves of water to see them through a drought; others send roots deep down to subsurface water supplies. But once these plants use up their stored reserve or tap out the underground supply, they cease growing and start to die. They may be able to handle a drought of some length, and many people use the term 'drought tolerant' to describe such plants, but they never actually stop needing to consume water, so Farrant prefers to call them drought resistant. F. Resurrection plants, defined as those capable of recovering from holding less than 0.1 grams of water per gram of dry mass, are different. They lack water-storing structures, and their existence on rock faces prevents them from tapping groundwater, so they have instead developed the ability to change their metabolism. When they detect an extended dry period, they divert their metabolisms, producing sugars and certain stress-associated proteins and other materials in their tissues. As the plant dries, these resources take on first the properties of honey, then rubber, and finally enter a glass-like state that is 'the most stable state that the plant can maintain,' Farrant says. That slows the plant's metabolism and protects its dried-out tissues. The plants also change shape, shrinking to minimize the surface area through which their remaining water might evaporate. They can recover from months and years without water, depending on the species. G. What else can do this dry-out-and-revive trick? Seeds—almost all of them. At the start of her career, Farrant studied 'recalcitrant seeds (顽拗性种子),' such as avocados, coffee and lychee. While tasty, such seeds are delicate—they cannot bud and grow if they dry out (as you may know if you've ever tried to grow a tree from an avocado pit). In the seed world, that makes them rare, because most seeds from flowering plants are quite robust. Most seeds can wait out the dry, unwelcoming seasons until conditions are right and they sprout (发芽). Yet once they start growing, such plants seem not to retain the ability to hit the pause button on metabolism in their stems or leaves. H. After completing her Ph.D. on seeds, Farrant began investigating whether it might be possible to isolate the properties that make most seeds so resilient (迅速恢复活力的) and transfer them to other plant tissues. What Farrant and others have found over the past two decades is that there are many genes involved in resurrection plants' response to dryness. Many of them are the same that regulate how seeds become dryness-tolerant while still attached to their parent plants. Now they are trying to figure out what molecular signaling processes activate those seed-building genes in resurrection plants—and how to reproduce them in crops. 'Most genes are regulated by a master set of genes,' Farrant says. 'We're looking at gene promoters and what would be their master switch.' I. Once Farrant and her colleagues feel they have a better sense of which switches to throw, they will have to find the best way to do so in useful crops. 'I'm trying three methods of breeding,' Farrant says: conventional, genetic modification and gene editing. She says she is aware that plenty of people do not want to eat genetically modified crops, but she is pushing ahead with every available tool until one works. Farmers and consumers alike can choose whether or not to use whichever version prevails: 'I'm giving people an option.' J. Farrant and others in the resurrection business got together last year to discuss the best species of resurrection plant to use as a lab model. Just like medical researchers use rats to test ideas for human medical treatments, botanists use plants that are relatively easy to grow in a lab or greenhouse setting to test their ideas for related species. The Queensland rock violet is one of the best studied resurrection plants so far, with a draft genome (基因图谱) published last year by a Chinese team. Also last year, Farrant and colleagues published a detailed molecular study of another candidate, Xerophyta viscosa, a tough-as-nail South African plant with lily-like flowers, and she says that a genome is on the way. One or both of these models will help researchers test their ideas—so far mostly done in the lab—on test plots. K. Understanding the basic science first is key. There are good reasons why crop plants do not use dryness defenses already. For instance, there's a high energy cost in switching from a regular metabolism to an almost-no-water metabolism. It will also be necessary to understand what sort of yield farmers might expect and to establish the plant's safety. 'The yield is never going to be high,' Farrant says, so these plants will be targeted not at Iowa farmers trying to squeeze more cash out of high-yield fields, but subsistence farmers who need help to survive a drought like the present one in South Africa. 'My vision is for the subsistence farmer,' Farrant says. 'I'm targeting crops that are of African value.'

单选题 As the economic role of multinational, global corporations expands, the international economic environment will be shaped increasingly not by governments or international institutions, but by the interaction between governments and global corporations, especially in the United States, Europe, and Japan. A significant factor in this shifting world economy is the trend toward regional trading blocs of nations, which has a potentially large effect on the evolution of the world trading system. Two examples of this trend are the United, States, Canada Free Trade Agreement (FTA. and Europe 1992, the move by the European Community (EC. to dismantle impediments to the free flow of goods, services, capital, and labor among member states by the end of 1992. However, although numerous political and economic factors were operative in launching the move to integrate the EC's markets, concern about protectionism within the EC does not appear to have been a major consideration. This is in sharp contrast to the FTA, the overwhelming reason for that bilateral initiative was fear of increasing United States protectionism. Nonetheless, although markedly different in origin and nature, both regional developments are highly significant in that they will foster integration in the two largest and richest markets of the world, as well as provoke question about the future direction of the world trading system.