单选题Paper sold to a publishing industry ______.

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 They say that sticks and stones may break your bones, but words will never hurt you. Yet childhood bullying really can damage your long-term health. Gone are the days when bullying was considered an inevitable and ultimately harmless part of growing up—just last month we learned that childhood bullying can lead to poorer mental health even into middle age. Now William Copeland at Duke University in Durham, North Carolina, and his colleagues have shown that it can have lingering physiological effects too. They tracked 1420 9-year-olds right through their teens. Each child was seen up to nine times during the study and quizzed about bullying. The team then measured levels of C-reactive protein in their blood. CRP is a marker of inflammation (炎症) linked to higher risk of cardiovascular disease (心血管疾病) and problems like diabetes. 'Because we were collecting biological samples throughout, we were able to look at CRP levels in subjects prior to their bullying involvement,' says Copeland. 'This really gives us an idea of the changes bullying brings about.' Although CRP levels naturally rise in everyone during adolescence, levels were highest in children who reported being tormented by bullies. Even at the ages of 19 and 21, children who had once been bullied had CRP levels about 1.4 times higher than peers who were neither perpetrators nor victims. In a cruel twist, the bullies had the lowest levels of all, suggesting they didn't suffer the same health risks. They may even see a benefit from their behavior, though Copeland stresses it doesn't vindicate (辩护) their actions. 'The goal would instead be to find other ways to produce this protective effect without it being at someone else's expense,' he says. Andrea Danese at King's College London has previously shown that maltreatment during childhood can lead to high levels of inflammation in adult life. 'This new study is a helpful addition in showing that these effects extend to another important childhood stressor,' he says. He suggests that care workers could monitor levels of CRP in children having psychotherapy to see if it is helping to soothe the stress of being bullied.

单选题If you ______ your influence, they may change their decision. A. compel B. exert C. expose D. vary

单选题City officials am considering building a path to give the public ______ to the site.

单选题More and more people today ______.

单选题The females in the rat population were ______ by the high population density.

单选题M: The taxi driver must have been speeding. W: Well, not really. He crashed into the tree because he was trying not to hit a box that had fallen off the truck ahead of him. Question: What do we learn about the taxi driver? A. He turned suddenly and ran into a tree. B. He was hit by a fallen box from a truck. C. He drove too fast and crashed into a truck. D. He was trying to overtake the truck ahead of him.

单选题We ______ building the bridge by the end of next month.

单选题 When families gather for Christmas dinner, some will stick to formal traditions dating back to Grandma's generation. Their tables will be set with the good dishes and silver, and the dress code will be Sunday best. But in many other homes, this china-and-silver elegance has given way to a stoneware (粗陶) and stainless informality, with dresses assuming an equally casual-Friday look. For hosts and guests, the change means greater simplicity and comfort. For makers of fine china in Britain, it spells economic hard times. Last week Royal Doulton, the largest employer in Stoke-on-Trent, announced that it is eliminating 1,000 jobs—one-fifth of its total workforce. That brings to more than 4,000 the number of positions lost in 18 months in the pottery (陶瓷) region. Wedgwood and other pottery factories made cuts earlier. Although a strong pound and weak markets in Asia play a role in the downsizing, the layoffs in Stoke have their roots in earthshaking social shifts. A spokesman for Royal Doulton admitted that the company 'has been somewhat slow in catching up with the trend' toward casual dining. Families eat together less often, he explained, and more people eat alone, either because they are single or they eat in front of television. Even dinner parties, if they happen at all, have gone casual. In a time of long work hours and demanding family schedules, busy hosts insist, rightly, that it's better to share a takeout pizza on paper plates in the family room than to wait for the perfect moment or a 'real' dinner party. Too often, the perfect moment never comes. Iron a fine-patterned tablecloth? Forget it. Polish the silver? Who has time? Yet the loss of formality has its down side. The fine points of etiquette (礼节) that children might once have learned at the table by observation or instruction from parents and grandparents ('Chew with your mouth closed.' 'Keep your elbows off the table.') must be picked up elsewhere. Some companies now offer etiquette seminars for employees who may be competent professionally but clueless socially.

单选题He was busy yesterday; otherwise he ______ to the meeting.

单选题According to a growing number of experts, it is already technically_____to construct a pioneering space colony, powered by solar energy.

单选题What is it that the author wants to ______ to his readers through the story?

单选题I come into ______with all kinds of people in my work.

单选题______from space, our earth, with water covering 70% of its surface, appears as a "blue planet".

单选题Today is the anniversary of that afternoon in April a year ago that I first saw the strange and appealing doll(玩具娃娃)in the window of Abe Sheftel's toy shop on Third Avenue near Fifteenth Street, just around the corner from my office, where the plate on the door reads: Dr. Samuel Amory. I remember just how it was that day: the first hint of spring floated across the East River, mixing with the soft-coal smoke from the factories and the street smells of the poor neighborhood. As I turned the comer on my way to work and came to Sheftel's, I was made once more aware of the poor collection of toys in the dusty window, and I remembered the approaching birthday of a small niece of mine in Cleveland, to whom I was in the habit of sending modest gifts. Therefore, I stopped and examined the window to see if there might be anything suitable, and looked at the confusing collection of unappealing objects- a red toy fire engine, some lead soldiers, cheap baseballs, bottles of ink, pens, yellowed envelopes, and advertisements for soft-drinks. And thus it was that my eyes eventually came to rest upon the doll stored away in one corner, a doll with the strangest, most charming expression on her face. I could not wholly make her out, due to the shadows and the film of dust through which I was looking, but I was aware that a tremendous impression had been made upon me as though I had run into a person, as one does sometimes with a stranger, with whose personality one is deeply impressed.

单选题Small animals are said to live faster than big ones because they ______.

单选题When it comes to human resources, hiring highly-skilled staff is not usually enough for a company to function successfully. Besides the knowledge in their particular fields, employees must always have additional skills—those of co-operation. In the case that work tasks can only be carried out by communicating with people, accepting common decisions, solving problems, sharing information and helping one another, teamwork skills are vital. While some jobs may require talent, the ability to work as a team is learned. There are no complicated formulas; you don"t need to have any special qualities or exceptional mental abilities. Individuals can be effective as a team if they have developed certain behaviors or habits of communication. Many companies, clubs and organizations use team building activities. Team building activities may include a number of teamwork elements. They are aimed at encouraging active participation in task accomplishment while all members have their roles as individuals and are able to co-operate towards a common goal as a team. Many team building activities focus on problem solving and discussing team issues; thus argument as a way to common consensus (共识) is encouraged. Team building activities often involve recognition and identification of team member skills, talents, knowledge, and experiences which allow the team members to learn more about each other and fully utilize those skills where appropriate. Many team activities are focused on developing keys to trust during challenging times.

单选题A lot of efforts have to be made in order to make this show ______.

单选题The jet quickly ______ into the sky and soon went out of our view. A. ascended B. launched C. assessed D. descended