单选题Multivitamins Urged for All Pregnant Women A recent study in Tanzania found that when pregnant women took vitamins every day, fewer babies were born too small. Babies that weigh less than two and one-half kilograms at birth have a greater risk of dying. Those that survive are more likely to experience problems with their development. And experts say that as adults they have a higher risk of diseases including heart disease and diabetes. The World Health Organization (WHO) estimates that every year twenty million babies are born with low birth weight. Nine out of ten of them are born in developing countries. The new study took place in Dares Salaam. 4,200 pregnant women received multivitamins. The pills contained all of the vitamins in the B group along with vitamins C and E. They also contained several times more iron and folate than the levels advised for women in developed nations. Pregnant women especially in poor countries may find it difficult to get enough vitamins and minerals from the foods in their diet. The scientists compared the findings with results from a group of 4,000 women who did not receive the vitamins. A report by the scientists, from the United States and Tanzania, appeared in the New England Journal of Medicine . Wafaie Fawzi of the Harvard University School of Public Health led the study. None of the women in the study had HIV, the virus that causes AIDS. The scientists reported earlier that daily multivitamins were a low-cost way to reduce fetal deaths in pregnant women infected with HIV. The earlier work in Tanzania also found improvement in the mothers in their number of blood cells known as lmphocytes. Lymphocytes increase the body"s immunity against infection. The new study in pregnant women who were not infected with the AIDS virus found that multivitamins reduced the risk of low birth weight. Just under eight percent of the babies born to women who took the multivitamins weighed less than 2,500 grams. The rate was almost nine and one-half percent in the group of women who received a placebo, an inactive pill, instead of the vitamins. But the vitamins did not do much to reduce the rates of babies being born too early or dying while still a fetus. Still, the researchers say multivitamins should be considered for all pregnant women in developing countries.

单选题 Explorer of the Extreme Deep Oceans cover more than two-thirds of our planet. Yet, just a small fraction of the underwater world has been explored. Now, scientists at the Woods Hotel Oceanographic Institution (WHOI) in Massachusetts are building an underwater vehicle that will carry explorers as deep as 6,500 meters (21,320 feet). The new machine, known as a manned submersible or human-operated vehicle (HOV), will replace another one named Alvin which has an amazing record of discovery, playing a key role in various important and famous undersea expeditions. Alvin has been operating for 40 years but can go down only 4,500 meters (14,784 feet). It's about time for an upgrade, WHOI researchers say. Alvin was launched in 1964. Since then, Alvin has worked between 200 and 250 days a year, says Daniel Fornari, a marine geologist and director of the Deep Ocean Exploration Institute at WHOI. During its lifetime, Alvin has carried some 12,000 people on a total of more than 3,000 dives. A newer, better versions of Alvin is bound to reveal even more surprises about a world that is still full of mysteries, Fornari says. It might also make the job of exploration a little easier. "We take so much for granted on land," Fornari says. "We can walk around and see with our eyes how big things are. We can see colors, special arrangements." Size-wise, the new HOV will be similar to Alvin. It'll be about 37 feet long. The setting area inside will be a small sphere, about 8 feet wide, like Alvin, it'll carry a pilot and two passengers. It will be just as maneuverable. In most other ways, it will give passengers more opportunities to enjoy the view, for one thing. Alvin has only three windows, the new vehicle will have five, with more overlaps so that the passengers and the pilot can see the same thing. Alvin can go up and down at a rate of 30 meters every second, and its maximum speed is 2 knots (about 2.3 miles per hour), while the new vehicle will be able to ascend and descend at 44 meters per second. It'll reach speeds of 3 knots, or 3.5 miles per hour.

单选题You must try to wipe out the memory of these horrible events.

单选题Get Right Amount of Vitamin D Vitamin D helps bones and muscles grow strong and healthy. Low levels of vitamin D can lead to problems like rickets and osteoporosis. Rickets is a deformity mainly found in children. Osteoporosis is the thinning of bone, a common problem as people, especially women, get older. Studies in recent years have suggested that vitamin D may also have other uses. Studies have shown that low levels of D may increase the risk of heart attacks in men and deaths from some cancers. Other studies have shown that people with rheumatic diseases often have low levels of D. The easiest way to get vitamin D is from sunlight. The ultraviolet rays react with skin cells to produce the vitamin. But many people worry about skin cancer and skin damage from the sun. Also, darker skinned people produce less vitamin D than lighter skinned people. Production also decreases in older people and those living in northern areas that get less sunlight. Not many foods naturally contain vitamin D. Foods with high levels include oily fish such as salmon, tuna and mackerel, and fish liver oils. Small amounts of D are found in beef liver, cheese and egg yolks. Most of the D in the American diet comes from foods like milk with the vitamin added. These days, more doctors are testing for vitamin D levels in their patients. But as research continues, some experts worry that if people take too much D, it might act as a poison. Also, skin doctors warn people to be careful with sun exposure. How much vitamin D does a healthy person need? Nutrition experts who advise the American government set the current recommendations in nineteen ninety -seven. The daily amount is two hundred international units from birth through age fifty. Then it rises to four hundred I. U. s through age seventy, and six hundred for those seventy--one and older. But some groups say these amounts are not high enough.

单选题She felt that she had done her good Udeed/U for the day.

单选题 Harmless Revenge Revenge is one of those things that everyone enjoys. People don't like to talk about it, though. Just the same, there is nothing more satisfying or more rewarding than revenge. The purpose is not to harm your victims but to let them know that you are upset about something that they are doing to you. Careful plotting can provide you with relief from bothersome co-workers, gossiping friends, or nagging family members. Co-workers who make comments about the fact that you are always fifteen minutes late for work can be taken care of very simply. All you have to do is get up extra early one day. Before the sun comes up, drive to each coworker's house. Reach under the hood of your coworker's ear and disconnect the center wire that leads to the distributor cap, the ear will be unharmed, but it will not Start, and your friends at work will all be late for work on the same day. If you're lucky, your boss might notice that you are the only one there and will give you a raise. Gossiping friends at school are also perfect targets for a simple act of revenge. A way to trap either male or female friends is to leave phony messages on their lockers. If the friend that you want to get is male, leave a message that a certain girl would like him to stop by her house later that day. With any luck, her boyfriend will be there. The girl won't know what's going on, and the victim will be so embarrassed that he probably won't leave his home for a month. When Morn and Dad and your sisters and brothers really begin to annoy you, harmless revenge may be just the way to make them quiet down for a while. The dinner table is a likely place. Just before the meal begins, throw a handful of raisins into the food. Wait about five minutes and, after everyone has begun to eat, cover your mouth with your hand and begin to make odd noises. When they ask you what the matter is, point to a raisin and yell, "Bugs!" They dump their food in the disposal, jump into the car, and head for McDonald's. That night, you'll have your first quiet, peaceful meal in a long time. A well-planned revenge does not have to hurt anyone. The object is simply to let other people know that they are beginning to bother you.

单选题Under-used computer equipment can proliferate in large companies without a system to {{U}}monitor{{/U}} purchasing.

单选题The manager {{U}}allocates{{/U}} duties to the clerks. A.assign B.persuade C.ask D.order

单选题UEfficient/U air service has been made available through modern technology.

单选题It was no surprise when we were told that our grandfather had passed away. A. survived B. gone out C. died D. gone on a trip

单选题If a thing is conspicuous by its absence, it is something that everyone expects to be there. A. noticeable B. necessary C. regrettable D. indifferent

单选题Exercise Lowers Employers" Health Costs Companies can save millions in health-care costs simply by encouraging their employees to exercise a little bit, researchers reported on Friday. They said obese (肥胖的) employees had higher health-care costs, but lowered those expenses by exercising just a couple of times a week — without even losing any weight. Feifei Wang and colleagues at the University of Michigan studied 23,500 workers at General Motors. They estimated that getting the most sedentary (惯于久坐的) obese workers to exercise would have saved about $790,000 a year, or about 1.5 percent of health-care costs for the whole group. Company-wide, the potential savings could reach $7.1 million per year, they reported in the Journal of Occupational and Environmental Medicine. Of the whole group of workers, about 30 percent were of normal weight, 45 percent were overweight (超重的), and 25 percent were obese. Annual health-care costs averaged $2,200 for normal weight, $2,400 for the overweight, and $2,700 for obese employees. But among workers who did no exercise, health-care costs went up by at least $100 a year, and were $3,000 a year for obese employees who were sedentary. But adding two or more days of light exercise — at least 20 minutes of exercise or work hard enough to increase heart rate and breathing — lowered costs by on average $500 per employee a year, the researchers found. "This indicates that physical activity behavior could reduce at least some of the harmful effects of excess body fat, and in consequence, help lower the health-care costs," Wang and colleagues wrote.

单选题Many economists have given in to the fatal Ulure/U of mathematics.

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}} Escaping from the Earth{{/B}} The Earth has a force that pulls things toward itself. We call this force gravity(地心引力). This is something we live with all the time, and we take it for granted and hardly ever think about it. But it is a most important factor in rocket operation and must be overcome if we are to get anywhere in space, or off the ground at all. Take the throwing of a ball as an example. The harder the ball is thrown, the faster and higher it will go. What is the secret? Its speed. If we could throw the ball hard enough it would go up and up forever and never come down. The speed at which it would have to be thrown to do this is known as escape speed. Of course, we cannot throw a ball hard enough because the speed required to escape completely from the Earth's gravity is seven miles per second, or over twenty-five thousand miles per hour. Once escape speed has been reached by a spacecraft(宇宙飞船), no further power is needed. A rocket aimed at the Moon, for instance, will "coast"(滑行) the rest of the way because the Earth's gravity cannot then pull it back, and there is no air resistance(阻力) in space to slow it down. This "coasting" is known as "free fall". That does not mean the rocket is falling down towards the Earth but that it is traveling freely in space without the aid of power, like a bicycle coasting downhill. Free fall is an important feature of space travel: it would be impossible to carry enough fuel to provide powered flight all the time.

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。 Skin Cancer Melanoma (黑素瘤), the deadliest kind of skin cancer, is now the most common cancer in{{U}} (51) {{/U}} British women, the country's leading cancer organization said Wednesday. Skin cancer has {{U}}(52) {{/U}} cervical (子宫颈的) cancer as the top cancer striking women in their 20s, according to the latest data from Cancer Research United Kingdom. The trend is particularly {{U}}(53) {{/U}} since younger people are not generally those most susceptible (易患的) to melanoma. Rates of skin cancer are {{U}}(54) {{/U}} highest in people over age 75. But experts worry that increasing numbers of younger people being diagnosed with skin cancer could be the {{U}}(55) {{/U}} of a dangerous trend. Women in their 20s make {{U}}(56) {{/U}} a small percentage of all patients diagnosed with melanoma in Britain, but nearly a third of all cases occur in people younger than 50. Based on current numbers, Cancer Research UK predicts that melanoma will become the fourth {{U}}(57) {{/U}} common cancer for men and women of all ages by 2024, and that cases will jump from about 9,000 cases a year to more than 15,500. Cancer experts {{U}}(58) {{/U}} the rising number of skin cancer cases largely to the surge in people using tanning salons. "Spending time on sun beds is just as {{U}}(59) {{/U}} as staying out too long in the sun," said Caroline Cerny of Cancer Research UK. The organization is starting a SunSmart {{U}}(60) {{/U}} to warn Britons of the dangers of being too bronzed. "The intensity of ultraviolet rays in some sun beds can be more than 10 {{U}}(61) {{/U}} stronger than the midday sun," Cerny said. In the United States, several states require parental approval {{U}}(62) {{/U}} minors can use tanning salons. Wisconsin bans people 16 and {{U}}(63) {{/U}} from using tanning beds, and others ban children under 14. At least 29 states have regulations governing minors' use of tanning salons. In the U. K. , Scottish politicians passed legislation banning those under 18 from using tanning beds, though it hasn't yet been implemented. There are no plans for {{U}}(64) {{/U}} in the rest of the U. K. The World Health Organization has previously recommended that tanning beds be regulated because of their potential to damage DNA in the skin. Experts said most deadly skin cancers could be {{U}}(65) {{/U}} if people took the proper precautions when in the sun and avoided tanning beds.

单选题Moderate Earthquake Strikes England A moderate earthquake struck parts of southeast England on 28 April 2007, toppling chimneys from houses and rousing residents from their beds. Several thousand people were left without power in Kent County. One woman suffered minor head and neck injuries. "It felt as if the whole house was being slid across like a fun-fair ride," said the woman. The British Geological Survey said the 4.3-magnitude quake struck at 8:19 a.m. and was centered under the English Channel, about 8.5 miles south of Dover and near the entrance to the Channel Tunnel. Witnesses said cracks appeared in walls and chimneys collapsed across the county. Residents said the tremor had lasted for about 10 to 15 seconds. "I was lying in bed and it felt as if someone had just got up from bed next to me," said Hedrick van Eck, 27, of Canterbury about 60 miles southeast of London. "I then heard the sound of cracking, and it was getting heavier and heavier. It felt as if someone was at the end of my bed hopping up and down." There are thousands of moderate quakes on this scale around the world each year, but they are rare in Britain. The April 28 quake was the strongest in Britain since 2002 when a 4.8-magnitude quake struck the central England city of Birmingham. The country"s strongest earthquake took place in the North Sea in 1931, measuring 6.1 on the Richter scale. British Geological Survey scientist Roger Musson said the quake took place on 28 April in an area that had seen several of the biggest earthquakes ever to strike Britain, including one in 1580 that caused damage in London and was felt in France. Musson predicted that it was only a matter of time before another earthquake struck this part of England. However, people should not be scared too much by this prediction, Musson said, as the modern earthquake warning system of Britain should be able to detect a forthcoming quake and announce it several hours before it takes place. This would allow time for people to evacuate and reduce damage to the minimum.

单选题The Usteadily/U rising cost of labor on the waterfront has greatly increased the cost of ship ping cargo by water.

单选题The employee was {{U}}accused of{{/U}} stealing the money.

单选题Sophonisba P. Breckinridge, the first woman admitted to the bar in Kentucky, eventually abandoned her legal career and became a social worker.

单选题Evidently, he has made a big mistake this time.A. likelyB. possiblyC. obviouslyD. simply