单选题He Uconfesses/U that he has done it.

单选题It came as something of a surprise when Diana, Princess of Wales, made a trip to Angola in 1997, to support the Red Cross's campaign for a total ban on all anti-personnel landmines. Within hours of arriving in Angola, television screens around the world were filled with images of her comforting victims injured in explosions caused by landmines. "I knew the statistics," she said, "But putting a face to those figures brought the reality home to me: like when I met Sandra, a 13-year-old girl who had lost her leg, and people like her. " The Princess concluded with a simple message: "We must stop landmines. " And she used every opportunity during her visit to repeat this message. But, back in London, her views were not shared by some members of the British government, which refused to support a ban on these weapons. Angry politicians launched an attack on the Princess in the press. They described her as "very ill-informed" and a "loose cannon" (乱放炮的人). The Princess responded by brushing aside the criticisms: "This is a distraction (干扰) we do not need. All I'm trying to do is help. " Opposition parties, the media and the public immediately voiced their support for the Princess. To make matters worse for the government, it soon emerged that the Princess's trip had been approved by the Foreign Office, and that she was in fact very well-informed about both the situation in Angola and the British government's policy regarding landmines. The result was a severe embarrassment for the government. To try and limit the damage, the Foreign Secretary, Malcolm Rifkind, claimed that the Princess's views on landmines were not very different from government policy, and that it was "working towards" a worldwide ban. The Defense Secretary, Michael Portillo, claimed the matter was "a misinterpretation or misunderstanding. " For the Princess, the trip to this war torn country was an excellent opportunity to use her ,popularity to show the world how much destruction and suffering landmines can cause. She said that the experience had also given her the chance to get closer to people and their problems.

单选题What can be concluded from the second and third paragraphs?

单选题What are my chances of promotion if I stay here?

单选题Most Adults in US Have Low Risk of Heart Disease More than 80 percent of US adults have a less than 10-percent risk of developing heart disease in the next 10 years, according to a report in the Journal of the American College of Cardiology. Just 3 percent have a risk that exceeds 20 percent. "I hope that these numbers will give physicians, researchers, health policy analysts, and others a better idea of how coronary heart disease is distributed in the US population," lead author Dr. Earl S. Ford, from the Centers for Disease Control and Prevention in Atlanta, said in a statement. The findings are based on analysis of data from 13,769 subjects, between 20 and 79 years of age, who participated in the Third National Health and Nutrition Examination Survey from 1988 to 1994. Overall, 82 percent of adults had a risk of less than 10 percent, 15 percent had a risk that fell between 10 to 20 percent, and 3 percent had a risk above 20 percent. The proportion of subjects in the highest risk group increased with advancing age, and men were more likely than women to be in this group. By contrast, race or ethnicity had little effect on risk distributions. Although the report suggests that most adults have a low 10-year risk of heart disease, a large proportion have a high or immediate risk, Dr. Daniel S. Berman, from Cedars-Sinai Medical Center in Los Angeles, and Dr. Nathan D. Wong, from the University of California at Irvine, note in a related editorial. Aggressive treatment measures and public health strategies are needed to shift the overall population risk downward, they add.

单选题You'll be agreeably surprised by its {{U}}reasonable{{/U}} price.

单选题California Gives Green Light to Space Solar Power Energy beamed down from space is one step closer to reality, now that California has given the green light to an agreement that would see the Pacific Gas and Electric Company buy 200 megawatt (兆瓦) of power beamed down from solar-power satellites beginning in 2016. But some major challenges will have to be overcome if the technology is to be used widely. A start-up company called Solaren is designing the satellites, which it says will use radio waves to beam energy down to a receiving station on Earth. The attraction of collecting solar power in space is the almost uninterrupted sunshine available in geosynchronous (与地球同步的) orbit. Earth-based solar cells, by contrast, can only collect sun light during daytime and when skies are clear. But space-based solar power must grapple (努力克服) with the high cost per kilogram of launching things into space, says Richard Schwartz of Purdue University in West Lafayette, Indiana. "If you"re talking about it being economically viable or power of the Earth, it"s a tough go," he says. Cal Boer man, Solaren"s director of energy services, says the company designed its satellites with a view to keeping launch costs down. "We knew we had to come up with a different, revolutionary design," he says. A patent the company has won describes ways to reduce the system"s weight, including using inflatable mirrors to focus sunlight on solar cells, so a smaller number can collect the same amount of energy. But using mirrors introduces other challenges, including keeping the solar cells from overheating, says Schwartz. "You have to take care of heat dissipation (散发) because you"re now concentrating a lot of energy in one place," he says. According to the company"s patent, Solaren"s solar cells will be connected to radiators to help keep them cool. Though Boer man says the company believes it can make space-based solar power work, it is not expecting to crowd out other forms of renewable energy. Laws in California and other states require increasing use of renewable energy in coming years, he points out. "To meet those needs, we"re going to need all types of renewable energy sources," he says.

单选题These factors interact intimately and cannot be separated.

单选题 Between 1986 and 1992 in the United States, mortality due to coronary heart disease among white men 45 to 74 years of age decreased by 26 percent, continuing a trend that began in the mid-1960s. Americans are thus doing something right. But did fish consumption help? This is where the Health Professionals Follow-Up(起作用) Study comes in. The study deals with the intake(摄影) of n-3 fatty acids and fish. The researchers calculated the intake of fish for 44,895 male health professionals—most of them dentists—in 1986 and kept track of their health status for the next six years. Surprisingly, the intake of n-3 fatty acids or fish in 1986 was not related to the risk of subsequent coronary disease. The number of participants was much larger than in other studies, and the methods and data analysis were solid. Also, measurements of fatty acids in adipose tissue showed that the questionnaire reliably ranked respondents according to their intake of n3 fatty acids. The researchers carefully spell out the limitations of the study. First, two thirds of the men had greatly increased their intake of fish over the 10 years before 1986. Some of those increases could have occurred. Shortly before the base-line investigation in 1986, because the inverse relation between fish consumption and mortality due to coronary heart disease was first reported in 1985. Thus, data on fish intake may not reflect long term habits, and changes in fish intake during follow-up could also have attenuated an association with coronary disease. The authors performed separate analyses including only men who reported no change in their fish intake and again found no effect. However, it is hard for people to recall whether they changed their diet several years ago. Second, the fish intake of these educated men was high and was more comparable with that of Norwegians or Japanese than with intake in the U.S. men studied previously. The epidemiologic data suggest that any beneficial effect is obtained with one or two servings of fish per week and that more is not better. Moreover, previous studies of fish intake have shown an association with the rate of mortality due to coronary disease, rather than with the incidence of nonfatal coronaty disease or coronary surgery. When seen in that light, there is some agreement between the present study and previous reports, because the risk of death from coronariy heart disease was about 25 percent lower among men who ate at least some fish than among those who ate no fish at all. A third limitation of the study was that some of the men studied may have begun to eat fish, or may have eaten more, because they thought that they were at increased risk of a heart attack;the men in the highest 20 percent of the study group in terms of their in-take of n-3 fatty acids more frequently reported a family history of coronary disease or a personal history of high cholesterol levels than men who ate less fish. The Harvard investigators concluded that increasing fish intake beyond one or two servings per week is unlikely to reduce the risk of coronary events substantially in men who are initially free of coronary disease. This is a prudent conclusion, and it could be extended to fish-oil capsules, which provide n-3 fatty acids in much larger amounts than are commonly consumed in food. The findings of the Health Professionals Follow-up Study should somewhat dampen enthusiasm for fish and fish oil as a panacea against coronary disease. A little fish may still do some good, but more fish is not necessarily better.

单选题Many city dwellers are turning vacant lots into thriving gardens.

单选题 UFOs Sixty years ago, a man named Kenneth Arnold saw something that we can still {{U}} {{U}} 1 {{/U}} {{/U}}today something that changed popular culture for ever. Flying his plane over mountains in the US state of Washington, he saw a line of strange objects, either crescent-shaped (月牙形的) or disc-like, flying {{U}} {{U}} 2 {{/U}} {{/U}}the motion of a saucer (碟) skimming (飞速掠过) on water. The media soon picked up on the story—the Flying Saucers were here! Was the earth being {{U}} {{U}} 3 {{/U}} {{/U}}by creatures from another planet? Soon, So many sightings were made that the US military began to {{U}} {{U}} 4 {{/U}} {{/U}}. It called these strange Objects UFOs—Unidentified Flying Objects, and that is how they are {{U}} {{U}} 5 {{/U}} {{/U}}today. Military investigations found no evidence of visitors from outer space. But that did not stop the true {{U}} {{U}} 6 {{/U}} {{/U}}. The military were {{U}} {{U}} 7 {{/U}} {{/U}}up, they said. Or maybe it was because the travelers from space were of such superior intelligence {{U}} {{U}} 8 {{/U}} {{/U}}they could hide from military analysts (分析家). People have always seen strange lights in the sky. In the past these were explained in {{U}} {{U}} 9 {{/U}} {{/U}}ways. In a world where religion was less influential and science fiction was popular, signs from God were replaced by visitors from other {{U}} {{U}} 10 {{/U}} {{/U}}. The date of the first UFO sightings was also significant. In 1947, World War Ⅱ had just ended and the {{U}} {{U}} 11 {{/U}} {{/U}}War was just beginning. Humanity seemed locked in endless conflicts. Like generations before them, people looked {{U}} {{U}} 12 {{/U}} {{/U}}the skies for help. But instead of seeking God, they looked for help from super-intelligent aliens (外星人) with {{U}} {{U}} 13 {{/U}} {{/U}}technology. Belief in UFOs became the first religion of science. However, even people who believe in UFOs are not quite sure why they visit the earth. The universe is a big place and it is {{U}} {{U}} 14 {{/U}} {{/U}}to assume that there is life somewhere out there. It is possible that aliens have worked out how to travel through space. Yet some people report that they have been taken by aliens and have had experiments {{U}} {{U}} 15 {{/U}} {{/U}}on them. Why would anyone travel across half the universe to conduct medical experiments on people living in small towns in the United States?

单选题Thousands of people perished in the storm.

单选题She could not answer, and it was an immense load off her heart.

单选题You must shine your shoes.

单选题The manager got angry because his secretary was ten minutes late.A. was in a bad moodB. lost his temperC. changed his mindD. have a passion

单选题British teenagers are damaging their health by not getting enough sleep because they are distracted by electronic gadgets in their bedrooms, according to a survey on Tuesday. The Sleep Council said "junk sleep" could compare with junk food as a major lifestyle matter for teenagers' parents. The poll of 1,000 teenagers aged 12 to 16 found that 30 percent managed just 4 to 7 hours' sleep, even though they are advised to sleep 8 or 9 hours. Almost a quarter said they fell asleep more than once a week while watching TV, listening to music or using other electronic gadgets. "This is a really worrying trend," said Dr Chris Idzikowski of the Edinburgh Sleep Centre. "What we are seeing is the result coming out of 'junk sleep' . It has neither length nor quality, both of which are important to feed the brain with the rest it needs to perform properly at school. " Nearly all the teenagers had a phone, music system or a TV in their bedrooms, and about two-thirds of the teenagers had all three of these things. Almost one in five teenage boys said the quality of their sleep had been influenced by their TVs or computers being left on. The survey also found that 40 percent of teenagers felt tired each day, with girls aged 15 to 16 feeling the worst. However, only 11 percent said they were bothered by the lack or bad quality of sleep. "I'm staggered that so few teenagers make the link between getting enough good quality sleep and bow they feel during the day," Idzikowski said. "Teenagers need to realize the fact that to feel well, perform well and look good, they need to do something about their sleep. /

单选题{{B}}第三篇{{/B}} Natural selection describes the biological process in which the differences of individuals within a population influences their abilities to survive and reproduce in an environment. The differences in individuals is a result of their genetic inheritance from their parents. In a population, any characteristic which blocks reproduction success tends to decrease generation by generation. In time, the ill-adapted die out. On the other hand,the individuals who do survive and reproduce will tend to produce offspring which are better adapted to the environment. Natural selection tends to promote adaptations that will increase the organism's ability to survive in an environment. Natural selection can serve to stabilize a population if the new traits, called mutations, are eliminated when they appear because they are not as well-adapted to the environment. The opposite effect is obtained when a new trait is introduced which allows individuals to adapt better over time, the species will change as this mutation becomes more widespread in the population. In human beings, increased brain size helped individuals to adapt better, and so brain size increased gradually in the species. Changes in the overall genetic makeup of a population are normal when there are environmental changes, especially sever environmental disruptions. Specialized adaptations to specific environments can lead, over time, to the development of subpopulation of individuals, ones who are better adapted to particular soil conditions food sources and so on. Given enough time, these subpopulations may develop into separate species, such as zebras and horses, living in distinct environments and not interbreeding.

单选题You can turn to different kinds of people, dictionaries or maps, to find out what you wish to know. A. contact B. consult C. refer D. request

单选题A 10-15 minutes’exercise will help you bear a heavier backpack.

单选题下面的短文有15处空白，请根据短文的内容为每处空白处确定一个最佳选项。 Happy Marriage, Happy Heart Happily married people have lower blood pressure {{U}}(51) {{/U}}unhappily married people or singles, a Brigham Young University study says. On the other hand, even having a supportive social network did not translate into a blood pres sure benefit for singles or unhappily {{U}}(52) {{/U}} people, according to the study. "There seem to be some unique health benefits from marriage. It's not just being married {{U}}(53) {{/U}} benefits health-what's really the most protective of health is having a happy {{U}}(54) {{/U}}" study author Julianne Hoh-Lunstad, a psychologist who specializes in relationships and health, said in a prepared statement. The study included 204 married and 99 {{U}}(55) {{/U}} adults who wore portable blood-pressure monitors for 24 hours. The {{U}}(56) {{/U}} recorded blood pressure at random intervals and provided a total of about 72 readings. "We wanted to capture participants' blood pressure doing whatever they normally {{U}}(57) {{/U}} in everyday life. Getting one or two readings in a clinic is not really {{U}}(58) {{/U}} of the fluctuations that occur throughout the day," Hoh-Lunstad said. Overall, happily married people scored four points {{U}}(59) {{/U}} on the blood pressure readings than single adults. The study also found that blood {{U}}(60) {{/U}} among married people--especially those in happy marriages--{{U}} (61) {{/U}}more during sleep than in single people. "Research has shown that people whose blood pressure remains high throughout the night are at {{U}}(62) {{/U}} greater risk of heart disease than people whose blood pressure drops. " Hoh-Lunstad said. The study was published in the March 20 {{U}}(63) {{/U}} of the journal Annals of Behavioral Medicine. The study also found that unhappily married adults have higher blood pressure than {{U}}(64) {{/U}} happily married and single adults. Hoh-Lunstad noted that married couples can encourage healthy habits in one {{U}}(65) {{/U}} such as eating a healthy diet and having regular doctor visits. People in happy marriages also have a source of emotional support, she said.