单选题If you make a mistake, {{U}}delete{{/U}} the characters you have entered using the backspace delete key.

单选题 下面的短文后列出了7个句子，请根据短文的内容对每个句子做出判断：如果该句提供的是正确信息，请选择A；如果该句提供的是错误信息，请选择B；如果该句的信息文中没有提及，请选择C。 {{B}}An Observation and an Explanation{{/B}} It is worth looking at one or two aspects of the way a mother behaves towards her baby. The usual fondling, cuddling and cleaning require little comment, but the position in which she holds the baby against her body when resting is rather revealing. Careful studies have shown the fact that 80 percent of mothers hold their infants in their left arms, holding them against the left side of their bodies. If asked to explain the significance of this preference most people reply that it is obviously the result of the predominance of right-handedness in the population. By holding the babies in their left arms, the mothers keep their dominant arm free for manipulations. But a detailed analysis shows that this is not the case. True, there is a slight difference between right-handed and left-handed females; but not enough to provide adequate explanation. It emerges that 83 percent of right-handed mothers hold the baby on the left side, but so do 78 percent of left-handed mothers. In other words, only 22 percent of the left-handed mothers have their dominant hands free for actions. Clearly there must be some other, less obvious explanation. The only other clue comes from the fact that the heart is on the side of the mother's body. Could it be that the sound of her heartbeat is the vital factor? And in what way? Thinking along these lines it was argued that perhaps during its existence inside the body of the mother the unborn baby get used to the sound of the heart beat. If this is so, then the re-discovery of this familiar sound after birth might have a claiming effect on the infant, especially as it has just been born into a strange and frighteningly new world. If this is so then the mother would, somehow, soon arrive at the discovery that her baby is more at peace if held on the left against her heart than on the right.

单选题You didn't Uadhere/U to these principles.

单选题Sleepwalking Not all sleep is the same every night. We experience some deep, quiet sleep and some active sleep, which is when dreams happen. You might think sleepwalking would happen during active sleep, but a person isn"t physically active during active sleep. Sleepwalking usually happens in the first few hours of sleep in the stage called slow-wave or deep sleep. Not all sleepwalkers actually walk. Some simply sit up or stand in bed or act like they"re awake when in fact, they"re asleep! Most, however, do get up and move around for a few seconds or for as long as half an hour. Sleepwalkers" eyes are open, but they don"t see the same way they do when they"re awake and often think they"re in different rooms of the house or different places altogether. Sleepwalkers tend to go back to bed on their own and they won"t remember it in the morning. Researchers estimate that about 15% of kids sleepwalk regularly. Sleepwalking may run in families (在家族中世代相传) and sometimes occurs when a person is sick, has a fever, is not getting enough sleep, or is stressed (紧张). If sleepwalking occurs frequently, every night or so, it"s a good idea for your mom or dad to take you to see your doctor. But occasional sleepwalking generally isn"t something to worry about, although it may look funny or even scary (骇人的) for the people who see a sleepwalker in action. Although occasional sleepwalking isn"t a big deal, it"s important, of course, that the person is kept safe. Precautions (预防措施) should be taken so the person is less likely to fall down, run into something, or walk out the front door while sleepwalking.

单选题The defeated troops were ordered to scatter and then concentrate fifty miles to the south.A. rallyB. attackC. marchD. retreat

单选题Studies Show US Spending Doesn't Get Best Health The United States may spend twice as much on health care as other rich countries but it is not getting results to match, according to studies released on Tuesday. But in the study of five wealthy countries, published in the journal Health Affairs, researchers found no single nation had clearly the worst or best health care system. Gerard Anderson at Johns Hopkins University's school of public health and colleagues came up with a list of 21 health fields they could evenly compare across the five countries — Australia, Canada, Britain, New Zealand and the United States. "None of the five countries is consistently the best or the worst on all 21 indicators," Anderson said during a telephone briefing for reporters. "If you are looking for the place to get the best care, there isn't a single place. Every country has at least one indicator where it scores the best of the five countries and each country has at least one indicator where it scores the worst of the five countries. " But, he said, the United States is not getting value for money. "The United States should be particularly concerned about these results, given that we spend twice as much on health care as any other country. So spending more doesn't necessarily result in better outcomes. Anderson's group of international health experts sponsored by the Commonwealth Fund spent five years working on the study, getting the latest possible data from the five countries on areas such as breast cancer and leukemia survival, suicide rates, death rates from asthma, vaccination rates and cancer screening.

单选题High Stress May Damage Memory According to a report issued in May 1998, elderly people who have consistently high blood levels of cortisol don't score as well on memory tests as their peers with lower levels of the stress hormone. What's more, high levels of cortisol are also associated with shrinking of the hippocampus, a region of the brain that plays a key role in learning and memory. The findings suggest that even cortisol levels in the normal, "healthy" range can actually acceIerate brain aging. The study results "now provide substantial evidence that long-term exposure to adrenal stress hormones may promote hippocampal aging in normal elderly humans", write Nada Porter and Philip Landfield of the University of Kentucky in Lexington in their editorial. Cortisol is a hormone released in response to stress by the adrenal glands, which sit on top of the kidneys. Over a 5 to 6-year period. Dr. Sonia Lupien and his colleagues measured 24-hour cortisol levels in 51 healthy volunteers, most of whom were in their 70s. Despite wide variation in cortisol levels, the participants could be divided into three subgroups: those whose cortisol progressively increased over time and was currently high (increasing/high); those whose cortisol progressively increased over time and was currently moderate (increasing/moderate); and subjects whose cortisol decreased, but was currently moderate (decreasing/moderate). The researchers tested the volunteers' memory on six people in the increasing/high category and five people in the decreasing/moderate group. The groups did not differ on tests of immediate memory, but the increasing/high cortisol group had other memory problems compared with those in the decreasing/moderate group. The researchers also found that the total volume of the hippocampus in those in the increasing/high group was 14% lower than those in the decreasing/moderate group, although there were no differences in other brain regions. The results suggest that " ... brain aging can be accelerated by levels of adrenal hormones that are not generally regarded as pathological and that variation within this normal range is related to variation in the rate of brain aging," write Porter and Landfield. "This further suggests that chronic stress may accelerate the worsening of hippocampus. /

单选题We've seen a {{U}}marked{{/U}} shift in our approach to the social issues.

单选题The purpose of the passage is to tell the reader

单选题 Dangers Await Babies with Altitude Women who live in the world's highest communities tend to give birth to underweight babies, a new study suggests. These babies may grow into adults with a high risk of heart disease and strokes. Research has hinted that newborns in mountain communities are lighter than average. But it wasn't clear whether this is due to reduced oxygen levels at high altitude or because their mothers are under-nourished—many people who live at high altitudes are relatively poor compared with those living lower down. To find out more, Dino Giussani and his team at Cambridge University studied the records of 400 births in Bolivia during 1997 and 1998. The babies were born in both rich and poor areas of two cities: La Paz and Santa Cruz. La Paz is the highest city in the world, at 3.65 kilometers above sea level, while Santa Cruz is much lower, at 0.44 kilometers. Sure enough, Giussani found that the average birthweight of babies in La Paz was significantly lower than in Santa Cruz. This was true in both high and low-income families. Even babies born to poor families in Santa Cruz were heavier on average than babies born to wealthy families in lofty La Paz. "We were very surprised by this result," says Giussani. The results suggest that babies born at high altitude are deprived of oxygen before birth. "This may trigger the release or suppression of hormones that regulate growth of the unborn child," says Giussani. His team also found that high-altitude babies tended to have relatively larger heads compared with their bodies. This is probably because a fetus starved of oxygen will send oxygenated blood to the brain in preference to the rest of the body. Giussani wants to find out if such babies have a higher risk of disease in later life. People born in La Paz might be prone to heart trouble in adulthood, for example. Low birthweight is a risk factor for coronary heart disease. And newborns with a high ratio of head size to body weight are often predisposed to high blood pres- sure and strokes in later life.

单选题Would you please Ucall/U my husband as soon as possible?

单选题I know you have made all the arrangements for the conference.A. appointmentsB. preparationsC. suggestionsD. ways

单选题Jack eventually Uovertook/U the last truck.

单选题They always mock me because I am ugly.

单选题Medicine Award Kicks off Nobel Prize Announcements Two scientists who have won praise for research into the growth of cancer cells could be candidates for the Nobel Prize in medicine when the 2008 winners are presented on Monday, kicking off six days of Nobel announcements. Australian-born U. S. citizen Elizabeth Blackburn and American Carol Greider have already won a series of medical honors for their enzyme research and experts say they could be among the front-runners for a Nobel. Only seven women have won the medicine prize since the first Nobel Prizes were handed out in 1901. The last female winner was U. S. researcher Linda Buck in 2004, who shared the prize with Richard Axel. Among the pair"s possible rivals are Frenchman Pierre Chambon and Americans Ronald Evans and Elwood Jensen, who opened up the field of studying proteins called nuclear hormone receptors. As usual, the award committee is giving no hints about who is in the running before presenting its decision in a news conference at Stockholm"s Karolinska Institute. Alfred Nobel, the Swede who invented dynamite, established the prizes in his will in the categories of medicine, physics, chemistry, literature and peace. The economics prize is technically not a Nobel but a 1968 creation of Sweden"s central bank. Nobel left few instructions on how to select winners, but medicine winners are typically awarded for a specific breakthrough rather than a body of research. Hans Jornvall, secretary of the medicine prize committee, said the 10 million kronor (US $ 1.3 million) prize encourages groundbreaking research but he did not think winning it was the primary goal for scientists. "Individual researchers probably don"t look at themselves as potential Nobel Prize winners when they"re at work," Jornvall told The Associated Press. "They get their kicks from their research and their interest in how life functions." In 2006,Blackburn, of the University of California, San Francisco, and Greider, of Johns Hopkins University in Baltimore, shared the Lasker prize for basic medical research with Jack Szostak of Harvard Medical School. Their work set the stage for research suggesting that cancer cells use telomerase to sustain their uncontrolled growth.

单选题After making observations for a week in the plant, the industrial engineer made a number of very constructive suggestions in an oral report to the manager. A. careful B. cautious C. deserved D. helpful

单选题Our statistics show that we {{U}}consume{{/U}} all that we are capable of producing:

单选题 下面的短文有15处空白，请根据短文内容为每处空白确定1个最佳选项。 {{B}}Many Children's Deaths Preventable: WHO{{/B}} Over five million children die each year from disease, infections and accidents related{{U}} (51) {{/U}}their environment although many of these deaths are largely preventable, says the World Health Organization. On Monday, the WHO asked governments and citizens around the world to take action to create healthy{{U}} (52) {{/U}}for children as it celebrated World Health Day. "The biggest threats to children's health lurk (潜藏) in the very{{U}} (53) {{/U}}that should be safest - home, school and community, said Dr. Gro Harlem Brundtland, director-general of the WHO at the day's launch in New Delhi, India. "Every child has the right to{{U}} (54) {{/U}}up in a healthy home, school and community. The future development of our children — and of their world — depends on{{U}} (55) {{/U}}enjoying good health now. We have their future in our{{U}} (56) {{/U}}. Now we must work more effectively together to{{U}} (57) {{/U}}the risks from the environment which our children face," Brundtland said. This year's theme, "Healthy Environments for Children" focuses on the many dangers{{U}} (58) {{/U}}by children in and around the places where they live and play. These include inadequate access to safe{{U}} (59) {{/U}}water and sanitation (卫生设备), insect-borne diseases, air pollution, chemical hazards and injuries from traffic, falls, burns and drownings. Communities around the world organized events to promote awareness of children's health issues, {{U}}(60) {{/U}}included drawing contests for schoolchildren in Vietnam, street plays in India, puppet (木偶) shows in Namibia and professional lectures for policy makers in Germany and elsewhere. Activities also took{{U}} (61) {{/U}}in cities across Canada on Monday, including Calgary, Montreal, Halifax and Ottawa. Although children under five represent only 10 per cent of the world's population, they bear 40 per cent of the global disease{{U}} (62) {{/U}}, says the WHO. And as much as one-third of the total burden of disease may be caused by environmental{{U}} (63) {{/U}}. World Health Day has been celebrated on April 7th{{U}} (64) {{/U}}1950. Each year the WHO chooses a theme to highlight areas of particular concern. Last year's{{U}} (65) {{/U}}, Move for Health, focuses on promoting physical activity as part of healthy living.

单选题HIV Vaccine Reduces Infection The vaccine -a combination of two earlier experimental vaccines -was given to 16,000 people in Thailand. Researchers found that it reduced by nearly a third the risk of contracting HIV, the virus that lcads to Aids. It has been hailed as a significant, scientific: breakthrough, but a global vaccine is still some way off. The study was carried out by the US army and the Thai government over seven years on volunteers - all HIV - negative men and women aged between 18 and 30 - in parts of Thailand. Half of the volunteers were given the vaccine, while the other half were given a placebo - and all were given counselling on HIV/Aids prevention. Participants were tested for HIV infection every six months for three years. The results found that the chances of catching HIV were 31.2% less for those who had taken the vaccine - with 74 people who did not get the vaccine infected and 51 of the vaccinated group infected. The vaccine is based on B and E strains of HIV that most commonly circulate in Thailand not the C strain which predominates in Africa. "This result is tantalisingly encouraging. The numbers are small and the difference may have been due to chance, but this finding is the first positive news in the Aids vaccine field for a decade," said Dr Richard Horton, editor of the Lancet medical joumal. "We should be cautious, but hopeful. The discovery needs urgent replication and investigation. " Dr Anthony Fauci, director of the US National Institute of Allergy and Infectious Diseases said: "For the first time, an investigational HIV vaccine has demonstrated some ability to prevent HIV infection amorig vaccinated individuals. " "Additional research is needed to better understand how this vaccine regimen reduced the risk of HIV infection, but this is certainly an encouraging advance for the HIV vaccine field. " The findings were hailed by the World Health Organization (WHO)and the Joint United Nations Programme on HIV/Aids (UN/Aids). They said while the results were" characterised as modestly protective... [they] have instilled new hope in the HIV vaccine research field".

单选题The original application card has gone astray.A. newB. includedC. outdatedD. lost