单选题The food is {{U}}insufficient{{/U}} for three people. A．instant B．infinite C inexpensive D．inadequate

单选题Charles Goodyear's discovery of vulcanized rubber began when he{{U}} inadvertently{{/U}} spilled a mixture of rubber and sulfur on a hot stove.

单选题There was a profound silence after his remark.

单选题Salt has been a respected commodity for much of recorded time.A. flavoringB. preservativeC. remedy for illnessD. article of trade

单选题 下面有3篇短文，每篇短文后有5道题，每题后面有4个选项。请仔细阅读短文并根据短文回答其后面的问题。{{B}}第一篇{{/B}} {{B}}Drug Reactions m a Major Cause of Death{{/B}} Adverse drug reactions may cause the deaths of over 100,000 US hospital patients each year, making them a leading cause of death nationwide, according to a report in the Journal of the American Medical Association. "The incidence of serious and fatal adverse drug reactions (ADRs) in US hospitals was found to be extremely high," say researchers at the University of Toronto in Ontario, Canada. They carried on an analysis of 39 ADR-related studies at US hospitals over the past 30 years and defined an ADR as "any harmful, unintended, and undesired effect of a drag which occurs at doses used in humans for prevention, diagnosis, or therapy." An average 6.7% of all hospitalized patients experience an ADR every year, according to the researchers. They estimate that "in 1994, overall 2,216,000 hospitalized patients had serious ADRs, and 106,000 had fatal ADRs." This means that ADRs may rank as the fourth single largest cause of death in America. And these incidence figures are probably conservative, the researchers add, since their ADR definition did not include outcomes linked to problems in drug administration, overdoses, drug abuse, and therapeutic failures. The control of ADRs also means spending more money. One US study estimated the overall cost of treating ADRs at up to $4 billion per year. Dr. David Bates of Brigham and Women's Hospital in Boston, Massachusetts, believes that healthcare workers need to pay more attention to the problem, especially since many ADRs are easily preventable. "When a patient develops an allergy or sensitivity, it is often not recorded," Bates notes, "and patients receive drugs to which they have known allergies or sensitivities with disturbing frequency." He believes computerized surveillance systems — still works-in-progress at many of the nation's hospitals — should help cut down the frequency of these types of errors.

单选题On average women lived longer than men 100-years ago.

单选题We explored the possibility of expansion at the conference.

单选题{{B}}第二篇{{/B}} {{B}} Common-cold Sense{{/B}} You can't beat it, but you don't have to join it. Maybe it got the name "common cold" because it's more common in winter. The fact is, though, being cold doesn't have anything to do with getting one. Colds are caused by the spread of rhinoviruses, and, at least so far, medical science is better at telling you how to avoid getting one than how to get rid of one. Children are the most common way cold viruses are spread to adults, because they have more colds than adults--an average of about eight per year. Why do kids seem so much more easily to get colds than their parents? Simple. They haven't had the opportunity to become immune to many cold viruses. There are more than 150 different cold viruses, and you never have the same one twice. Being infected by one makes you immune to it--but only it. Colds are usually spread by direct contact, not sneezing or coughing. From another person's hand to your hand and then to your nose or eyes is the most common route. The highest concentration of cold viruses anywhere is found under the thumbnails of a boy, although the viruses can survive for hours on skin or other smooth surfaces. Hygiene is your best defense. Wash your hands frequently, preferably with a disinfectant soap, especially when children in your household have colds. But even careful hygiene won't ward off. every cold. So, what works when a coughing, sneezing, runny nose strikes? The old prescription of two aspirins, lots of water, and bed rest is a good place to start. But you'll also find some of the folk remedies...Hot mixtures of sugar (or honey), lemon, and water have real benefits. rhinovirus n.鼻病毒 immune adj. 免疫的,有免疫力的 disinfectant n. 消毒剂,杀菌剂 sneeze vi. 打喷嚏 thumbnail n.拇指

单选题{{U}}While{{/U}} we don't agree, we continue to be friends. A. Whoever B. Where C. Although D. Whatever

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?