单选题The boss is impatient to novices.A. newcomersB. carpentersC. novelistsD. secretaries

单选题It is implied in the passage that the writer takes a(n) ______ attitude towards the mall.

单选题Can Buildings Be Designed to Resist Terrorist Attack? In the aftermath of the terrorist attack on the World Trade Center, structural engineers are trying hard to solve a question that a month ago would have been completely unthinkable: Can buildings be designed to withstand catastrophic blasts (爆炸) inflicted by terrorists? Ten days after the terrorist attacks on the twin towers, structural engineers from the University at Buffalo and the Multidisciplinary Center for Earthquake Engineering Research (MCEER) headquartered (总部在某地) at UB traveled to ground zero as part of a project funded by the National Science Foundation. Visiting the site as part of an MCEER reconnaissance (事先考查) visit, they spent two days beginning the task of formulating ideas about how to design such structures and to search for clues on how to do so in buildings that were damaged but still are standing. "Our objective in visiting ground zero was to go and look at the buildings surrounding the World Trade Center, those buildings that are still standing, but that sustained damage," said M. Bruneau, Ph.D. "Our immediate hope is that we can develop a better understanding as to why those buildings remain standing, while our long-term goal is to see whether earthquake engineering technologies can be married to existing technologies to achieve enhanced performance of buildings in the event of terrorist attacks," he added. Photographs taken by the investigators demonstrate in startling (惊人的) detail the monumental damage inflicted on the World Trade Center towers and buildings in the vicinity. One building a block away from the towers remains standing, but was badly damaged. "This building is many meters away from the World Trade Center and yet we see a column there that used to be part of that building," explained A. Whittaker, Ph. D. "The column became a missile that shot across the road, through the window and through the floor." The visit to the area also revealed some surprises, according to the engineers. For example, the floor framing system in one of the adjacent buildings was quite rugged, allowing floors that were pierced by tons of falling debris to remain intact. "Highly redundant ductile (有延展性的) framing systems may provide a simple, but robust strategy for blast resistance," he added. Other strategies may include providing alternate paths for gravity loads in the event that a load-bearing column fails. "We also need a better understanding of the mechanism of collapse," said A. Whittaker. "We need to find out what causes a building to collapse and how you can predict it." A. Reinhorn, Ph. D. noted that "Earthquake shaking has led to the collapse of many buildings in the past. It induces dynamic response and extremely high stresses and deformations in structural components. Solutions developed for earthquake-resistant design may be directly applicable to blast engineering and terrorist-resistant design. Part of our mission now at UB is to transfer these solutions and to develop new ones where none exist at present."

单选题Unpopular Subjects? Is there a place in today's society for the study of useless subjects in our universities? Just over 100 years ago Fitzgerald argued in a well-written letter (51) Nature that "Universities must be allowed to study useless subjects (52) they don't，who will?He went 0n to use the (53) of Maxwell's electrodynamics_(电动力学)as one case where a"useless subject" has been transformed to a useful subject． 　　Nowadays this argument is again very much (54) in many universities．Indeed one suspects that it is one of those arguments that must be (55) anew(重新)by each generation．But now there is an added twist ~)—subjects must not only be useful，they must also be (56) enough that students will flock(蜂拥)to d0 them，and even flock to pay to do them． 　　As universities become commercial operations，the pressure to (57) subjects or departments that are less popular will become stronger and stronger, Perhaps this is most strongly (58) at the moment by physics．There has been much (59) in the press of universities that are closing down physics departments and incorporate them with mathematics or engineering departments． 　　Many scientists think otherwise．They see physics as a (60) science，which must be kept alive if only to (61) a base for other sciences and engineering．It is of their great personal concern that physics teaching and research is under (62) in many universities．How Can it be preserved in the rush towards commercial competition? A major turnaround(转变)in student popularity may have to (63) until the industrial world discovers that it needs physicists and starts paying them well．Physics is now not only unpopular；it is also"hard"．We can do more about the latter by (64) teaching in our schools and universities．We can also (65) cooperative arrangements to ensure that physicists keep their research and teaching up to date.

单选题The river widens considerably as it begins to turn east. A. extends B. stretches C. broadens D. travels

单选题What Is the Coolest Gas in the Universe? What is the coldest air temperature ever recorded on the Earth? Where was this low temperature recorded? The coldest recorded temperature on Earth was -91℃, which (51) in Antarctica in 1988. We encounter an interesting situation when we discuss temperatures in (52) . Temperatures in Earth orbit actually range from about 20℃ to 120℃. The temperature depends upon (53) you are in direct sunlight or shade. Obviously, -120℃ is colder than our body can safely endure. Thank NASA science for well-designed space (54) that protect astronauts from these temperature extremes. The space temperatures just discussed affect only our area of the solar (55) . Obviously, it is hotter closer to the Sun and colder as we travel away from the Sun. Astronomers estimate temperatures at Pluto are about -210℃. How cold is the lowest estimated temperature in the entire universe? Again, it depends upon your (56) . We are taught it is supposedly (57) to have a temperature below absolute zero, which is -273℃, at which atoms do not move. Two scientists, whose names are Cornell and Wieman, have successfully cooled down a gas to a temperature barely (58) absolute zero. They won a Nobel Prize in Physics in 2001 for their work—not a discovery, in this case. Why is the two scientists work so important to science? In the 1920s, Satyendra Nath Bose was studying an interesting (59) about special light particles we now call photons. Bose had trouble (60) other scientists to believe his theory, (61) he contacted Albert Einstein. Einstein's calculations helped him theorize that atoms (62) behave as Bose thought—but only at very cold temperatures. Scientists have also discovered that (63) atoms can help them make the world's atomic docks even more accurate. These clocks are so accurate today they would only lose one second (64) six million years! Such accuracy will help us travel in space because distance is velocity times time (d=vt). With the long distances involved in space (65) , we need to know time as accurately as possible to get accurate distance.

单选题It is necessary that the membership applications should be Udispatched/U immediately.

单选题A large crowd Uassembled/U outside the American embassy.

单选题A person who deals with the public must be {{U}}courteous{{/U}} at all times, even when he or she is very tired.

单选题The movie has a {{U}}satisfying{{/U}} ending.

单选题The story was touching .

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.