单选题______ in a simple style, the book clearly describes the author' s childhood experiences in a small town.A. WritingB. To be writtenC. Being writtenD. Written

单选题The Californian redwoods, the tallest trees in the world, are known for their ability to withstand fire, insects and disease.A. bearB. resistC. attackD. defend

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℃ to 70℃. At 30℃, 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 U.S. States Do Poorly in Women's Health Not a single U.S. state meets basic federal goals for women's health, and the nation as a whole fails except in two areas—mammograms (乳腺X光照片) and dental (牙齿的) check-ups—researchers said on Thursday. Millions of women lack health insurance, and states make it difficult to enroll (加入) in Medicaid, the state-federal health insurance plan for the poor, according to the report. And few states are doing anywhere near enough to help women quit smoking—the leading cause of death in the United States. "The nation as a whole and the individual states fall short of meeting national goals," reads the report, put together by the National Women's Law Center (NWLC) and the Oregon Health & Science University. "These health goals provide a road map for assessing the status of women's health." Of 27 measures examined by the group, from screening for diseases to actually treating them, the nation passes on only two, the researchers said. "The nation is so far from the health goals that it receives an overall grade of 'unsatisfactory'," they wrote. The problem seems to be a lack among states of an overall plan for health in general, the NWLC said. "State policy makers' piecemeal (一件一件做的) approach to our health care crisis has resulted in a complex and ineffective system that fails to meet the health care needs of women," Judy Waxman, NWLC Vice President for Health, said in a statement. "Lawmakers need to take a comprehensive, long-term approach to meeting women's health needs and tackle this serious problem that troubles so many families. "

单选题Bacteria Bacteria are extremely small living things. While we measure our own sizes in inches or centimeters, bacterial size is measured in microns. One micron is a thousand of a millimeter: a pinhead is about a millimeter across. Rod-shaped bacteria are usually from two to four microns long, while rounded ones are generally one micron in diameter. Thus if you enlarged a rounded bacterium a thousand times, it would be just about the size of a pinhead. An adult human magnified by the same amount would be over a mile (1. 6 kilometers) tall. Even with an ordinary microscope, you must look closely to see bacteria. Using a magnification of 100 times, one finds that bacteria are barely visible as tiny rods or dots. One cannot make out anything of their structure. Using special stains, one can see that some bacteria have attached to them wavy-looking " hairs" called flagella. Others have only one flagellum. The flagella rotate, pushing the bacteria through the water. Many bacteria lack flagella and cannot move about by their own power, while others can glide along over surfaces by some little-understood mechanism. From the bacterial point of view, the world is a very different place from what it is to humans. To a bacterium water is as thick as molasses is to us. Bacteria are so small that they are influenced by the movements of the chemical molecules around them. Bacteria under the microscope, even those with no flagella, often bounce about in the water. This is because they collide with the water molecules and are pushed this way and that. Molecules move so rapidly that within a tenth of a second the molecules around a bacterium have all been replaced by new ones; even bacteria without flagella are thus constantly exposed to a changing environment.

单选题A Tale of Scottish Rural Life Lewis Grassic Gibbon's Sunset Sony, (1932) was voted "the best Scottish novel of all time" by Scottish's reading public in 2005. Once considered shocking for its frank description of aspects of the lives of Scotland's poor rural farmers, it has been adapted for stage, film, TV and radio in recent decades. The novel is set on the fictional estate of Kinraddie, in the fanning country of the Scottish northwest in the years up to and beyond World War I. At its heart is the story of Chris, who is both part of the community and a little outside it. Grassic Gibbon gives us the most detailed and intimate account of the life of his heroine. We watch her grow through a childhood dominated by her cruel but hard-working father; experience tragedy (her mother's suicide and murder of her twin children); and learn about her feelings as she grows into woman. We see her marry, lose her husband, then marry again. Chris has seemed so convincing a figure to some female readers that they cannot believe that she is the creation of a man. But it would be misleading to suggest that this book is just about Chris. It is truly a novel of a place and its people. Its opening section tells of Kinraddie's long history, in a language that imitates the place's changing patterns of speech and writing. The story itself is amazingly full of characters and incidents. It is told from Chris' point of view but also from that of the gossiping community, a community where everybody knows everybody else's business and nothing is ever forgotten. Sunset Song has a social theme too. It is concerned with what Grassic Gibbon perceives as the destruction of traditional Scottish rural life first by modernization and then by World War I. Gibbon tried hard to show how certain characters resist the war. Despite this, the war takes the young men away, a number of them to their deaths. In particular, it takes away Chris' husband, Ewan Tavendale. The war finally kills Ewan, but not in the way his widow is told In fact, the Germans aren't responsible for his death, but his own side. He is shot because he is said to have run away from a battle. If the novel is about the end of one way of life it also looks ahead, it is a "Sunset Song" but is concerned too with the new Kinraddie, indeed of the new European world Grassic Gibbon went on to publish two other novels about the place that continue its story.

单选题It took us a long time to {{U}}mend{{/U}} the house

单选题William Wrigley sent free gum to every pretty woman in the US.

单选题Since 1939, numerous studies have been conducted to determine whether smoking is a health hazard. The trend of the evidence has been consistent and indicates that there is a serious health risk. Research teams have conducted studies that show beyond all reasonable doubt that tobacco smoking is associated with a shortened life expectancy. Cigarette smoking is believed by most research workers in this field to be an important factorin the development of caner of the lungs and cancer of the throat and is believed to be related to cancer of some other organs of the body. Male cigarette smokers have a higher death rate from bean disease than non--smoking males. Female smokers are thought to be less affected because they do not breathe in the smoke so deeply. Apart from statistics, it might be helpful to look at what smoking tobacco does to the human body. Smoke is a mixture of gases, vaporized chemicals, minute particles of ash and other solids. There is also nicotine, which is powerful poison, and black tar. As smoke is breathed in, all those components from deposits on the membranes of the lungs. One point of concentration is where the air tube and bronchus divides. Most lung cancer begins at this point. Filters and low tar tobacco are claimed to make smoking to some extent safer, but they can only slightly reduce, not eliminate the hazards. What is the main idea of the passage?A. Smoking is big hazard to health.B. There are ways to make smoking safe.C. Smoking is more hazardous to male smokers than to female smokers.D. There are many poisonous chemicals in tobacco.

单选题At the first explosion, the crowd {{U}}scattered{{/U}}. A. separated B. fled C. departed D. spread

单选题"Much of the sickness and death attributed to the major communicable diseases is in fact caused by malnutrition which makes the body less able to withstand infections when they strike," said Dr Hiroshi Nakajima, Director-General of the World Health Organization (WHO). "At the same time," he added, "in developing countries today, malnutrition is the cause of 174 million children under five years of age being (51) , and 230 million being stunted(阻碍)in their growth. Such (52) represent deprivation, suffering and wasted human potential (53) a scale that is unacceptable from every point of view. Whether we think in (54) of humanitarian concern, common justice or development needs, they demand a (55) , both from national governments and from the international community." It is now (56) that 6.6 million out of the estimated 12.2 million deaths (57) among children under-five--or 54% of young child mortality in developing countries-is associated with malnutrition, In some (58) , such as sub-Saha-ran Africa and south Asia, stagnation(停滞)of nutritional improvement (59) with a rapid rise in population has resulted in an (60) increase in the total number of malnourished children. (61) , over two-thirds of the world's malnourished children live in Asia (especially south Asia), followed by Africa and Latin America. As Dr Nakajima noted, "The globalization of industry, trade, travel and communication has brought (62) it unprecedented possibilities for mutual cooperation in (63) hunger and malnutrition. At the same time, however, the acceptability of certain foods, and the cultural aspects of their production, distribution and preparation, are now recognized as (64) in the promotion of good nutrition. Without the attention (65) them, little progress can be made towards household food security, appropriate diets, the control of micronutrient(微量元素)deficiencies, the promotion of breast-feeding, and other strategies listed in the Plan of Action adopted in 1992 (at the International Conference on Nutrition in Rome)./

单选题Since speech is such a familiar activity, it is often regarded as a universal {{U}}endowment{{/U}}.

单选题Lack of Sleep Increases the Risk of Catching a Cold As cold season approaches, many Americans stock up on their vitamin C and Echinacea (紫锥花精油). But fallowing the age -old advice about catching up on sleep might be more important. Studies have demonstrated that poor sleep and susceptibility (易受影响) to colds go hand in hand, and scientists think it could be a reflection of the role sleep plays in maintaining the body's defenses. In a recent study for the Archives of Internal Medicine, scientists followed 153 men and women for two weeks, keeping mack of their quality and duration of sleep. Then, during a five - day period, they quarantined (进行检疫隔离) the subjects and exposed them to cold viruses. Those who slept an average of fewer than seven hours a night, it turned out, were three times as likely to get sick as those who averaged at least eight hours. Sleep and immunity, it seems, are tightly linked. Studies have found that mammals that require the most sleep also produce greater levels of disease - fighting white blood cells--but not red blood cells, even though both are produced in bone marrow (骨髓) and stem from the same precursor (前体物). And researchers at the Max Planck Institute for Evolutionary Anthropology have shown that species that sleep more have greater resistance against pathogens (病原体). "Species that have evolved longer sleep durations," the Planck scientists wrote, "appear to be able to increase investment in their immune systems and be better protected. /

单选题In order to improve our standard of living, we have to {{U}}accelerate{{/U}} production. A. involve B. decrease C. speed up D. give up

单选题The transportation of goods and people from place to place continues to gain in efficiency through technology.A. vehiclesB. boxesC. commoditiesD. machines

单选题She exhibited great powers of endurance during the climb.

单选题U.S. Eats Too Much Salt People in the United States consume more than twice the recommended amount of salt, raising their risk for high blood pressure, heart attacks and strokes, government health experts said on Thursday. They found nearly 70 percent of U.S. adults are in high-risk groups that would benefit from a lower-salt of no more than 1,500mg per day, yet most consume closer to 3,500mg per day. "It"s important to eat less salt. People who adopt a heart healthy eating pattern that includes a diet low in sodium and rich in potassium and calcium can improve their blood pressure," Dr. Darwin Labarthe of the Centers for Disease Control and Prevention said in a statement. "People need to know their recommended daily sodium limit and take action to reduce sodium intake," Labarthe said. The study in CDC"s report on death and disease used national survey data to show that two out of three adults should be consuming no more than 1,500 mg of sodium per day because they are black or over the age of 40—which are considered high-risk groups. Yet studies show most people in the United States eat 3,436 mg of sodium per day, according to a 2005-2006 CDC estimate. Most of the sodium eaten comes from package, processed and restaurant foods. The CDC said it will join other agencies in the Health and Human Services department in working with major food manufacturers and chain restaurants to reduce sodium levels in the food supply. Nationwide, 16 million men and women have heart disease and 5.8 million are estimated to have had a stroke. Cutting salt consumption can reduce these risks, the CDC said.

单选题The architecture is harmonious and no building is over six-storey high.

单选题They all think that the price of personal computers will soon plunge.

单选题Going Back to Its Birthplace No sporting event takes hold of the world"s attention and imagination like the Olympic Games. The football World Cup fascinates fans in Europe and South America; baseball"s World Series is required viewing in North America; and the World Table Tennis Championships attracts the most interest in Asia. But the Olympics belong to the whole world. NOW, after travelling to 17 countries over 108 years, the summer Games are returning to Athens, the place where the first modern Olympics was held. Participation in the Games is looked on not only as an achievement, but also as an honor. The 16 days between August 13 and 29 will see a record—202 countries compete, up from Sydney"s 199. Afghanistan is back, having been banned from Sydney because the Taliban government didn"t let women do sports. There is also a place for newcomers East Timer and Kiribati. A total of 10,500 athletes will compete in 28 sports, watched by 53 million ticket-paying viewers as well as a television audience of 4 billion. Athens is to use its rich history and culture to make the Olympics as special as possible. The Games will open with cycling events which start in front of the Parthenon and Acropolis monuments. The final event will be a historic men"s marathon following the Original route run by Phidippides in 490 B.C. to bring news of victory over the Persians. The ancient stadium at Olympia, first used for the Games nearly three centuries ago, will stage the shot put competitions. And the Panathenian Stadium, where the first modern Olympics was held, is to host the archery (射箭) events. If the well-known ancient sites deliver a great sense of history to the Games, the 39 new venues add a modern touch to the city of Athens. The main Olympic stadium, with a giant glass and steel roof, is the landmark (标志) building of the Olympics. "We believe that we will organize a "magical" Games." said Athens 2004 President Gianna Angelopoulos Daskalaki. "Our history with the Olympic Gaines goes back nearly 3,000 years, and Athens 2004 could be the best ever."