单选题An old friend called on me the day before yesterday.

单选题Chinese scientists moved people away from the coming quake zone after noticing the strange behavior of some animals and physical changes in earth.

单选题The children trembled with fear when they saw the policeman.

单选题A Uspokeswoman/U for the company promised that they would investigate our complaint.

单选题Double Effect The Supreme Court's decisions on physician-assisted suicide carry important implications for how medicine seeks to relieve dying patients of pain and suffering. Although it ruled that there is no constitutional right to physician-assisted suicide, the Court in effect supported the medical principle of "double effect", a centuries-old moral principle holding that an action having two effects—a good one that is intended and a harmful one that is foreseen—is permissible if the actor intends only the good effect. Doctors have used that principle in recent years to justify using high doses of morphine to control terminally ill patients' pain. even though increasing dosages will eventually kill the patient. Nancy Dubler, director of Montefiore Medical Center, contends that the principle will shield doctors who "until now have very, very strongly insisted that they could not give patients sufficient mediation to control their pain if that might hasten death. " George Annas, chair of the health law department at Boston University, maintains that, as long as a doctor prescribes a drug for a legitimate medical purpose, the doctor has done nothing illegal even if the patient uses the drug to hasten death. "It's like surgery, " he says. "We don't call those deaths homicides because the doctors didn't intend to kill their patients, although they risked their death. If you're a physician, you can risk your patient's suicide as long as you don't intend their suicide. " On another level, many in the medical community acknowledge that the assisted-suicide debate has been fueled in part by the despair of patients for whom modern medicine has prolonged the physical agony of dying. Just three weeks before the Court's ruling on physician-assisted suicide, the National Academy of Science (NAS) released a two-volume report, Approaching Death: Improving Care at the End of Life. It identifies the under-treatment of pain and the aggressive use of "ineffectual and forced medical procedures that may prolong and even dishonor the period of dying" as the twin problems of end-of-life care. The profession is taking steps to require young doctors to train in hospices, to test knowledge of aggressive pain management therapies, to develop a Medicare billing code for hospital-based care, and to develop new standards for assessing and treating pain at the end of life. Annas says lawyers can play a key role in insisting that these well-meaning medical initiatives translate into better care. "Large numbers of physicians seem unconcerned with the pain their patients are needlessly and predictably suffering, " to the extent that it constitutes "systematic patient abuse. " He says medical licensing boards "must make it clear... that painful deaths are presumptively ones that are incompetently managed and should result in license suspension. /

单选题Albert Einstein, whose theories on space time and matter helped unravel(解开) the secrets of the atom and of the universe, was chosen as "Person of the Century" by Time Magazine on Sunday. A man whose very name is synonymous with scientific genius, Einstein has come to represent more than any other person the flowering of the 20[th] century scientific thought that set the stage for the age of technology. "The world has changed far more in the past 100 years than in any other century in history. The reason is not political or economic, but technological-technologies that flowed directly from advances in basic science," wrote theoretical physicist Stephen Hawking in a Time essay explaining Einstein's significance. "Clearly no scientist better represents those advances than Albert Einstein." Time chose as runner-up (第二名) President Franklin Roosevelt to represent the triumph of freedom and democracy over fascism, and Mahatma Gandhi as an icon (象征) for a century when civil and human rights became crucial factors in global politics. Who was chosen as top "Person of the Century" by Time magazine last week?A. Franklin Roosevelt.B. Mahatma Gandhi.C. Thomas Edison.D. Albert Einstein.

单选题Late-Night Drinking Coffee lovers beware. Having a quick "pick-me-up" cup of coffee late in the day will play havoc with your sleep. As well as being a stimulant, caffeine interrupts the flow of melatonin, the brain hormone that sends people into a sleep. Melatonin levels normally start to rise about two hours before bedtime. Levels then peak between 2 am and 4 am, before falling again. "It's the neurohormone that controls our sleep and tells our body when to sleep and when to wake," says Maurice Ohayon of the Stanford Sleep Epidemiology Research Center at Stanford University in California. But researchers in Israel have found that caffeinated coffee halves the body's levels of this sleep hormone. Lotan Shilo and a team at the Sapir Medical Center in Tel Aviv University found that six volunteers slept less well after a cup of caffeinated coffee than after drinking the same amount of decal. On average, subjects slept 336 minutes per night after drinking caffeinated coffee, compared with 415 minutes after decal. They also took half an hour to drop off— twice as long as usual—and jigged around in bed twice as much. In the second phase of the experiment, the researchers woke the volunteers every three hours and asked them to give a urine sample. Shilo measured concentrations of a breakdown product of melatonin. The results suggest that melatonin concentrations in caffeine drinkers were half those in decaf drinkers. In a paper accepted for publication in Sleep Medicine, the researchers suggest that caffeine blocks production of the enzyme that drives melatonin production. Because it can take many hours to eliminate caffeine from the body, Ohayon recommends that coffee lovers switch to decaf after lunch.

单选题 Europa's Watery under World Europa, one of Jupiter's 63 known moons, looks bright and icy on the surface. But appearances can be deceiving: Miles within its cracked, frigid shell, Europa probably hides giant pools of liquid water. Where scientists find liquid water, they hope to find life as well. Since we can't go diving into Europa's depths just yet, scientists instead have to investigate the moon's surface for clues to what lies beneath. In a new study, scientists investigated one group of strange ice patterns on Europa and concluded that the formations mark the top of an underground pool that holds as much water as the U. S. Great Lakes. Pictures of Europa, which is slightly smaller than Earth's moon, clearly show a tangled, icy mishmash of lines and cracks known as "chaos terrains." These chaotic places cover more than half of Europa. For more than 10 years, scientists have wondered what causes the formations. The new study suggests that they arise from the mixing of vast underground stores of liquid water with icy material near the surface. For scientists who suspect that Europa also may be hiding life beneath its icy surface, the news about the new lake is exciting. "It would be great if these lakes harbored life, " Britney Schmidt, a planetary scientist who worked on the study, told Science News. "But even if they didn't, they say that Europa is doing something interesting and active right now. " Schmidt, a scientist at the University of Texas at Austin, and her colleagues wanted to know how chaos terrains form. Since they couldn't rocket to Europa to see for themselves, they searched for similar formations here on Earth. They studied collapsed ice shelves in Antarctica and icy caps on volcanoes in Iceland. Those features on Earth formed when liquid water mixed with ice. The scientists now suspect something similar might be happening on Europa: that as water and ice of different temperatures mingle and shift, the surface fractures. This would explain the jumbled ice sculptures. "Fracturing catastrophically disrupts the ice in the same way that it causes ice shelves to collapse on Earth, " Schmidt told Science News. She and her team found that the process could be causing chaos terrains to form quickly on Europa. The new study suggests that on this moon, elements such as oxygen from the surface blend with the deep bodies of water. That mixture may create an environment that supports life.

单选题Volcanic fire and glacial ice are natural enemies. Eruptions at glaciated volcanoes typically destroy ice fields, as they did in 1980 when 70 percent of Mount Saint Helens ice cover was de molished. During long dormant intervals, glaciers gain the upper hand cutting deeply into volcanic cones and eventually reducing them to rubble. Only rarely do these competing forces of heat and cold operate in perfect balance to create phenomenon such as the steam caves at Mount Rainier Park. Located inside Rainier's two ice-filled summit craters, these caves form a labyrinth of tunnels and vaulted chambers about one and one-half miles in total length. Their creation depends on an unusual combination of factors that nature almost never brings together in one place. The cave-making recipe calls for a steady emission of volcanic gas and heat, a heavy annual snowfall at an elevation high enough to keep it from melting during the summer, and a bowl-shaped crater to hold the snow. Snow accumulating yearly in Rainier's summit craters is compacted and compressed into a dense form of ice called firn, a substance midway between ordinary ice and the denser crystalline ice that makes up glaciers. Heat rising from numerous openings (called fumaroles) along the inner crater walls melts out chambers between the rocky walls and the overlying ice pack. Circulating currents of warm air then melt additional opening in the firn ice, eventually connecting the individual chambers and, in the larger of Rainier's two craters, forming a continuous passageway that extends two-thirds of the way around the crater' s interior. To maintain the cave system, the elements of fire under ice must remain in equilibrium, Enough snow must fill the crater each year to replace that melted from below. If too much volcanic heat is discharged, the crater' s ice pack will melt away entirely and the caves will vanish along with the snows of yesteryear. If too little heat is produced, the ice replenished annually by winter snowstorms will expand, pushing against the enclosing crater wails and smothering the present caverns in solid firn ice.

单选题Renewable Energy Sources Today petroleum(石油) provides around 40% of the world"s energy needs, mostly fuelling automobiles. Coal is still used, mostly in power stations, to cover one-quarter of our energy needs, but it is the least efficient, unhealthiest and most environmentally damaging fossil fuel(矿物燃料). Natural gas reserves could fill some of the gap from oil, but reserves of that will not last into the 22nd century either. Most experts predict we will exhaust easily accessible reserves within 50 years. Less-polluting renewable energy sources offer a more practical long-term energy solution. "Renewable" refers to the fact that these resources are not used faster than they can be replaced. Hydroelectric(水力发电的)power is now the most common form of renewable energy, supplying around 20% of world electricity. China"s Three Gorges Dam is the largest ever. At five times the size of the U.S."s Hoover Dam, its 26 turbines(涡轮机) will generate the equivalent energy of 18 coal-fired power stations. It will satisfy 3% of China"s entire electricity demand. In 2003, the first commercial power station to use tidal (潮汐的)currents in the open sea opened in Norway. It is designed like windmill(风车), but others take the form of turbines. As prices fall, wind power has become the fastest growing type of electricity generation—quadrupling(翻两番) worldwide between 1999 and 2005. Modern wind farms consist of turbines that generate electricity. Though it will be more expensive, there is more than enough wind to provide the world"s entire energy needs. Wind farms come in onshore and offshore forms. They can often end up at spots of natural beauty, and are often unpopular with residents. And turbines are not totally harmless—they can interfere with radar, alter climate and kill sea birds. Scotland is building Europe"s largest wind farm, which will power 200,000 homes. The U.K."s goal is to generate one-fifth of power from renewable sources, mainly wind, by 2020. But this may cause problems, because wind is unreliable.

单选题I enjoy the dish a lot. Can I have the prescription for it?

单选题Some comments are just Uinviting/U trouble.

单选题Computer Mouse The basic computer mouse is an amazingly clever invention with a relatively simple design that allows us to point at things on the computer and it is very productive. Think of all the things you can do with a mouse like selecting text for copying and pasting (涂), drawing, and even scrolling on the page with the newer mice with the wheel. Most of us use the computer mouse daily without stopping to think how it works until it gets dirty and we have to learn how to clean it. We learn to point at things before we learn to speak, so the mouse is a very natural pointing device. Other computer pointing devices include light pens, graphics (图形) tablets and touch screens, but the mouse is still our workhorse. The computer mouse was invented in 1964 by Douglas Englehart of Stanford University. As computer screens became more popular and arrow keys were used to move around a body of text, it became clear that a pointing device that allowed easier motion through the text and even selection of text would be very useful. The introduction of the mouse, with the Apple Lisa computer in 1983, really started the computer public on the road to relying on the mouse for routine (常规) computer tasks. How does the mouse work? We have to start at the bottom, so think upside down for now. It all starts with the mouse ball. As the mouse ball in the bottom of the mouse rolls over the mouse pad, it presses against and turns two shafts (轴). The shafts are connected to wheels with several small holes in them. The wheels have a pair of small electronic light-emitting devices called light-emitting diodes (LED) mounted on either side. One LED sends a light beam to the LED on the other side. As the wheels spin and a hole rotates by, the light beam gets through to the LED on the other side. But a moment later the light beam is blocked until the next hole is in place. The LED detects (发现) a changing pattern of light, converts the pattern into an electronic signal, and sends the signal (发信号) to the computer through wires in a cable that goes out the mouse body. This cable is the tail that helps give the mouse its name. The computer interprets the signal to tell it where to position the cursor on the computer screen. So far we have only discussed the basic computer mouse that most of you probably have or have used. One problem with this design is that the mouse gets dirty as the ball rolls over the surface and picks up dirt. Eventually you have to clean your mouse. The newer optical mice avoid this problem by having no moving parts.

单选题阅读下面的短文，文中有15处空白，每处空白给出了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。 {{B}}A Wonderful Chip{{/B}} It is tiny, only about a quarter of an inch square, and quite flat. Under a microscope, it resembles a stylized Navaho rug or the aerial view of a railroad{{U}} (51) {{/U}}yard. Like the{{U}} (52) {{/U}}of sand on a beach, it is made mostly of silicon,{{U}} (53) {{/U}}oxygen, the most abundant element on the surface of the earth. Yet this inert fleck (小片), still unfamiliar to the{{U}} (54) {{/U}}majority of Americans, has astonishing power. It is cheap to{{U}} (55) {{/U}}produce, fast, infinitely versatile and convenient. The miracle chip represents a quantum(重大的){{U}} (56) {{/U}}in the technology of mankind, a development that{{U}} (57) {{/U}}the past few years has acquired the force and significance associated with the development of hand tools or the discovery of the steam engine. Just as the Industrial Revolution{{U}} (58) {{/U}}an immense{{U}} (59) {{/U}}of tasks from men’s{{U}} (60) {{/U}}and enormously expanded productivity,{{U}} (61) {{/U}}the microcomputer is rapidly assuming huge burdens of drudgery from the human brain and{{U}} (62) {{/U}}expanding the mind’s capacities{{U}} (63) {{/U}}that man has only begun to grasp.{{U}} (64) {{/U}}the chip amazing feats of{{U}} (65) {{/U}}become possible in everything from automobile engines to university laboratories and hospitals, from farms to banks and corporate offices, from outerspace to a baby’s nursery.

单选题We must get to the root of the problem.

单选题Without the greenhouse gases, the earth would

单选题 Male-Female Expectation about Marriage The differences between men and women clarify why they have different expectations about communication in marriage. For women, talk {{U}} {{U}} 1 {{/U}} {{/U}}intimacy. Marriage is an orgy (狂欢) of {{U}} {{U}} 2 {{/U}} {{/U}}: you can tell your feelings and thoughts, and still be loved. Women's greatest fear is being pushed away. But men live in a hierarchical world, {{U}} {{U}} 3 {{/U}} {{/U}}talk maintains independence and statue. They are on {{U}} {{U}} 4 {{/U}} {{/U}}to protect themselves from being put down and pushed around. This {{U}} {{U}} 5 {{/U}} {{/U}}the paradox of the talkative man who said of his silent wife, "She's the talker." In public settings, he feels challenged to {{U}} {{U}} 6 {{/U}} {{/U}}his intelligence and display his understanding. But at home, where he has {{U}} {{U}} 7 {{/U}} {{/U}}to prove and no one to defend against, he is free to remain {{U}} {{U}} 8 {{/U}} {{/U}}. For his wife, being home means she is free from the worry that something she says might {{U}} {{U}} 9 {{/U}} {{/U}}someone, or spark disagreement, or appear to be showing off; at home she is {{U}} {{U}} 10 {{/U}} {{/U}}to talk. The communication {{U}} {{U}} 11 {{/U}} {{/U}}that endanger marriage can't be fixed by mechanical engineering. They require a new conceptual framework about the {{U}} {{U}} 12 {{/U}} {{/U}}of talk in human relationships. Many of the psychological explanations may not be {{U}} {{U}} 13 {{/U}} {{/U}}, because they tend to blame either women (for not being assertive enough) {{U}} {{U}} 14 {{/U}} {{/U}}men (for not being in touch with their feelings). A sociolinguistic approach in {{U}} {{U}} 15 {{/U}} {{/U}}male-female conversation is seen as cross-cultural communication allows us to understand the problem and forge solutions without blaming either party.

单选题There had not been such a severe storm in Trumbull County for a hundred years.

单选题The book provides a concise analysis of the country"s history.

单选题Maria Chapman, abolitionist and close associate of William Lloyed Garrison, wrote many brochures condemning slavery.