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.

单选题{{B}}第二篇{{/B}} {{B}} Stress Level Tied to Education Level{{/B}} People with less education suffer fewer stressful days, according to a report in the current issue of the Journal of Health and Social Behavior. However, the study also found that when less-educated people did suffer stress it was more severe and had a larger impact on their health. From this researchers have concluded that the day-to-day factors that cause stress are not random. Where you are in society determines the kinds of problems that you have each day, and how well you will cope with them. The research team interviewed a national sample of 1,031 adults daily for eight days about their stress level and health. People without a high school diploma reported stress on 30 percent of the study days, people with a high school degree reported stress 38 percent of the time, and people with college degrees reported stress 44 percent of the time. "Less advantaged people are less healthy on a dally basis and are more likely to have downward turns in their health." lead researcher Dr. Joseph Grzywacz, of Wake Forest University Baptist Medical Center, said in a prepared statement. "The downward turns in health were connected with daily stressors, and the effect of daily stressors on their health is much more devastating for the less advantaged." Grzywacz suggested follow-up research to determine why less-educated people report fewer days of stress when it is known their stress is more acute and chronic. "If something happens every day, maybe it's not seen as a stressor." Grzywacz says. "Maybe it is just life." stressor n. 紧张性刺激 devastating adj. 毁灭性的 follow-up n. (对病人的) 随访

单选题The walrus uses its tusks to dig food from the ocean bottom.

单选题During the past ten years there have been dramatic changes in the international situation.

单选题The farmer {{U}}chased{{/U}} sheep into a wheat field.

单选题It is easy to misjudge the strength of the wind.A. forceB. directionC. temperatureD. effect

单选题Universities usually give diplomas or certificates to students who complete course requirements Uadequately/U.

单选题 阅读下面的短文，文中有15处空白，每处空白给出4个选项，请根据短文的内容从4个选项中选择1个最佳答案。 Nearly three in 10 men have experienced violence at the hands of an intimate partner during their lifetimes, according to one of the few studies to look{{U}} (51) {{/U}}domestic violence and health among men. "Many men actually do experience domestic violence, although we don't hear about it{{U}} (52) {{/U}}," Dr. Robert J. Reid of the University of Washington in Seattle, one of the authors, told Reuters Health. "They often don' t tell{{U}} (53) {{/U}} we don' t ask. We want to get the message out to men who{{U}} (54) {{/U}}experience domestic violence that they are not alone and there are resources available to{{U}} (55) {{/U}}" The researchers asked study participants about physical abuse and non-physical {{U}}(56) {{/U}}such as threats that made them{{U}} (57) {{/U}}for their safety, controlling behavior (for example, being told who they could associate with and where they could go), and constant name-calling. Among men 18 to 54 years old, 14.2 percent said they had experienced intimate partner{{U}} (58) {{/U}}in the past five years, while 6. 1 percent reported domestic violence in the previous year. Rates were lower for men 55 and{{U}} (59) {{/U}}, with 5.3 percent reporting violence in the past five years and 2.4 percent having experienced it in the past 12 months. Overall, 30.5 percent of men younger than 55 and 26.5 percent of older men said they had been victims of{{U}} (60) {{/U}}violence at some point in their lives. About half of the violence the men{{U}} (61) {{/U}}was physical. However, the physical violence men reported wasn't as harsh as{{U}} (62) {{/U}}suffered by women in a previous study; 20 percent to 40 percent of the men rated it as severe, compared to 61 percent of{{U}} (63) {{/U}}. Men who reported experiencing domestic violence had more emotional and mental problems{{U}} (64) {{/U}} those who had not, especially older men, the{{U}} (65) {{/U}}found.

单选题My keys were here a minute ago but now they've vanished.A. disappearedB. movedC. appearedD. left

单选题{{B}}第三篇{{/B}} {{B}}Population Densities{{/B}} The average population density (密度) of the world is 47 persons per square mile. Continental densities range from no permanent inhabitants in Antarctica to 211 per square mile in Europe. In the western hemisphere, population densities range from about 4 per square mile in Canada to 675 per square mile in Puerto Rico. In Europe the range is from 4 per square mile in Iceland to 831 per square mile in the Netherlands. Within countries there are wide variations of population densities. For example, in Egypt, the average is 55 persons per square mile, but 1,300 person inhabit each square mile in settled portions where the land is arable (适合耕种的). High population densities generally occur in regions of developed industrialization, such as the Netherlands, Belgium, and Great Britain, or where lands are intensively used for agriculture, as in Puerto Rico and Java. Low average population densities are characteristic of most underdeveloped countries. Low density of population is generally associated with a relatively low percentage of cultivated land. This generally results from poor quality lands. It may also be due to natural obstacles to cultivation, such as deserts, mountains, or malaria-infested (疟疾横行的) jungles; to land uses other than cultivation, as pasture and forested land; to primitive methods that limit cultivation; to social obstacles. More economically advanced countries of low population density have, as a rule, large proportions of their populations living in urban areas. Their rural population densities are usually very low. Poorly developed countries of correspondingly low population density, on the other hand, often have a concentration of rural population living on arable land, which is as great as the rural concentration found in the most densely populated industrial countries.