单选题These old buildings are gorgeous .

单选题Dinner Order As any homemaker who has tried to keep order at the dinner table knows, there is far more to a family meal than food. Sociologist Michael Lewis has been studying 50 families to find out just how much more. Lewis and his co-workers carried out their study by videotaping the families while they ate ordinary meals in their own homes. They found that parents with small families talk actively with each other and their children. But as the number of children gets larger, conversation gives way to the parents" efforts to control the loud noise they make. That can have an important effect on the children. "In general the more question-asking the parents do, the higher the children"s IQ scores," Lewis says. "And the more children there are, the less question-asking there is." The study also provides an explanation for why middle children often seem to have a harder time in life than their siblings. Lewis found that in families with three or four children, dinner conversation is likely to center on the oldest child, who has the most to talk about, and the youngest, who needs the most attention. "Middle children are invisible," says Lewis. "When you see someone get up from the table and walk around during dinner, chances are that it"s the middle child." There is, however, one thing that stops all conversation and prevents anyone from having attention. "When the TV is on," Lewis says, "dinner is a non-event."

单选题I asked Lily whether she wanted to go swimming with me and she {{U}}nodded{{/U}}.

单选题By the time the war {{U}}broke out{{/U}}, most of the people had already left.

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}} Earthquake{{/B}}{{B}}How does an earthquake start?{{/B}}What makes an earthquake happen? The rock of the earth's crust (地壳) may have a 'fault', a kind of break in the surface. The blocks which make up the earth move, and sometimes this may cause the sides of the fault to move up and down or lengthways (纵向地) against each other. When one piece of rock starts to rub on another with great force, a lot of energy is used. This energy is changed into vibrations (振动) and it is these vibrations that we feel as an earthquake. The vibrations can travel thousands of kilometers and so an earthquake in Turkey may be felt in Greece.{{B}}What to do during an earthquake?At school{{/B}}As soon as the earthquake starts, students should get under the desks immediately and wait until the teacher tells them it is safe to come out. The teacher should, at the same time, go immediately to the teacher's desk, get underneath (在......下面) it and stay there till the danger is over. Students must not argue with the teacher or question instructions. As soon as the tremors (震动) stop, all students should walk towards the exit and go straight to the school playground or any open space such as a square or a park. They must wait there until the teacher tells them it is safe to go.{{B}}At home{{/B}}If you are at home when the earthquake occurs, get immediately under the table in the living room or kitchen. Choose the biggest and strongest table you can find. You must not go anywhere near the window and don't go out onto the balcony (阳台). Once the tremors have stopped, you can come out from under the table but you must leave the building straight away. You should walk down the stairs and should not use the lift - there may be a power cut as a result of the earthquake and you could find yourself trapped inside the lift for hours.{{B}}In the street{{/B}}If you are in. the street when the earthquake takes place, do not stand near buildings, fences or walls - move away as quickly as possible and try to find a large open space to wait in. Standing under trees could also be dangerous.

单选题It can beinferred from the last paragraph that brown dwarfs.

单选题Electronic Mail During the past few years, scientists all over the world have suddenly found themselves productively engaged in task they once spent their lives avoiding—writing, any kind of writing, but particularly letter writing. Encouraged by electronic mail"s surprisingly high speed, convenience and economy, people who never before touched the stuff are regularly, skillfully, even cheerfully tapping out a great deal of correspondence. Electronic networks, woven into the fabric of scientific communication these days, are the route to colleagues in distant countries, shared data, bulletin boards and electronic journals. Anyone with a personal computer, a modern and the software to link computers over telephone lines can sign on. An estimated five million scientists have done so with more joining every day, most of them communicating through a bundle of interconnected domestic and foreign routes known collectively as the Internet, or net. E-mail is starting to edge out the fax, the telephone, overnight mail, and of course, land mail. It shrinks time and distance between scientific collaborators, in part because it is conveniently asynchronous (异步的) (Writer can type while their colleagues across time zones sleep; their message will be waiting.). If it is not yet speeding discoveries, it is certainly accelerating communication. Jeremy Bernstein, the physicist and science writer, once called E-mail the physicist"s umbilical cord (脐带). Later other people, too, have been discovering its connective virtues. Physicists are using it; college students are using it; everybody is using it; and as a sign that it has come of age, the New Yorker has celebrated its liberating presence with a cartoon—an appreciative dog seated at a keyboard, saying happily, "On the Internet, nobody knows you"re a dog."

单选题Unless Uchecked/U, rabbits can generate rapidly when conditions are in their favor.

单选题Dark Forces Dominate Universe The earth, moon, sun and all visible stars in the sky make up less than one percent of the universe. Almost all the rest is dark matter and dark energy, unknown 1 that puzzle astronomers. Observations in recent years have changed the basic understanding of how the universe evolved and have emphasized for astronomers how little is known 2 the major forces and substances that shaped our world. Astronomers now know that luminous matter-stars, planets and hot gas— 3 only about 0.4 percent of the universe. Non-luminous components, such as black holes and intergalactic gas, make up 3.6 percent. The rest is either dark matter, about 23 percent, or dark energy, about 73 percent. Dark matter, sometimes called "cold dark matter," has been known for some 4 . Only recently have researchers come to understand the pivotal role it 5 in the formation of stars, planets and even people. "We owe our very existence to dark matter," said physicist Paul Steinhardt and a co-author of a review on dark matter which appeared not long 6 in the journal Science. Steinhardt said it is believed that following the Big Bang, the theoretical 7 of the universe, dark matter caused particles to clump together. That set up the gravitation processes that led to the formation of stars and galaxies. Those stars, in turn, created the basic chemicals, such as carbon and iron, that were 8 to the evolution of life. "Dark matter dominated the formation of structure in the early universe." Steinhardt said. "For the first few billion years dark matter contained 9 of the mass of the universe. You can think of ordinary matter as a froth of an Ocean of dark matter. The dark matter clumps and the ordinary matter falls into it. That led to the 10 of the stars and galaxies." Without dark matter, "there 11 be virtually no structures in the universe." The nature of dark matter is 12 . It cannot be seen or detected 13 . Astronomers know it is there because of its effect on celestial objects than can be seen and measured. But the most dominating force of 14 in the universe is called dark energy. A recently proven power that astronomers say is causing the galaxies in the universe to separate at a faster and faster speed. One scientist said it is clear now 15 dark matter and dark energy engaged in a gravitational tug of war that, eventually, dark energy won.

单选题The dolphin leapt up into the air because Sagan was too near the water.

单选题These factors interact intimately and cannot be separated. A. tensely B. nearly C. carefully D. closely

单选题It doesn't {{U}}stand to reason{{/U}} that he would lie. A. seem logical B. look pleasant C. appear obvious D. sound important

单选题I recognized him {{U}}right away{{/U}} even though Richard disguised well.

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：如果该句提的是正确信息，请选择A：如果该句提的是错误信息，请选择B：如果该句的信息文中没有提及，请选择C。 Irradiating Food Irradiating fruits, vegetables, pork and chicken to kill insects and bacteria has been approved by the Food and Drug Administration over the past decade. Irradiation of other meats, such as beef and lamb, is being reviewed. Federal approval does not require that industry adopt the process, and few food processors presently offer irradiated products. Market studies have shown that many consumers are afraid that eating irradiated foods may cause cancer, despite scientific studies that prove the safety of treated foods. Some people argue that more severe government inspection, higher food-safety standard and more careful-preparation practices by consumers are all that is needed to ensure that food is safe. Consequently, companies currently see no need to spend millions of dollars outfitting processing plants with the equipment necessary for a process that very few shoppers are in favor of. All supermarkets that sell irradiated food must label the food either directly on the packaging, or, in the case of bulk items like fruits and vegetables, by placing a sign nearby. There is no requirement for the labeling of irradiated food served by chain restaurants or hospitals that buy directly from distributors, nor any regulations for products that contain irradiated ingredients. Presently, the FDA allows food to be treated with three types of radiation -- gamma rays (伽马射线), high-energy electrons, and X rays -- and sets limits on doses, depending on the type of food. The principle is that the dose to be used for a certain type of food should not exceed the amount that is sufficient to kill most harmful insects and bacteria present in it. Different types of food, because of their molecular compositions, may require different doses of radiation.

单选题She felt hurt by my words, but it wash' t really out of my intention.A. purposeB. indicationC. implicationD. invasion

单选题If headaches only {{U}}occur{{/U}} at night, lack of fresh air is often the cause. A. deliver B. fall C. happen D. arrive

单选题 Pool Watch Swimmers can drown in busy swimming pools when lifeguards fail to notice that they are in trouble. The Royal Society for the Prevention of Accidents says that on average 15 people drown in British pools each year, hut many more suffer major injury after getting into difficulties. Now a French company has developed an artificial intelligence system called Poseidon that sounds the alarm when it sees someone in danger of drowning. When a swimmer sinks towards the bottom of the pool, the new system sends an alarm signal to a poolside monitoring station and a lifeguard's pager. In trials at a pool in Ancenis, near Nantes, it saved a life within just a few months, says Alistair McQuade, a spokesman for its maker, Poseidon Technologies. Poseidon keeps watch through a network of underwater and overheard video cameras. AI software analyses the images to work out swimmers trajectories. To do this reliably, it has to tell the difference between a swimmer and the shadow of someone being cast onto the bottom or side of the pool. "The underwater environment is a very dynamic one, with many shadows and reflections dancing around." says McQuade. The software does this by "projecting" a shape in its field of view onto an image of the far wail of the pool. It does the same with an image from another camera viewing the shape from a different angle. If the two projections are in the same position, the shape is identified as a shadow and is ignored. But if they are different, the shape is a swimmer and so the system follows its trajectory. To pick out potential drowning victims, anyone in the water who starts to descend slowly is added to the software's "pre-alert" list, says McQuade. Swimmers who then stay immobile on the pool bottom for 5 seconds or more are considered in danger of drowning. Poseidon double-checks that the image really is of a swimmer, not a shadow, by seeing whether it obscures the pool's floor texture when viewed from overhead. If so, it alerts the lifeguard, showing the swimmer's location on a poolside screen. The first full-scale Poseidon system will be officially opened next week at a pool in High Wycombe, Buckinghamshire. One man who is impressed with the idea is Travor Baylis, inventor of the clockwork radio. Baylis runs a company that installs swimming pools, and he was once an underwater escapologist with a circus. "I say full marks to them if this works and can save lives," he says. But he adds that any local authority spending ￡30,000-plus on a Poseidon system ought to be investing similar amounts in teaching children to swim.

单选题The old concerns lose importance and some of them Uvanish/U altogether;

单选题During his lifetime he was able to {{U}}accumulate{{/U}} quite a fortune. A. control B. spend C. collect D. exchange

单选题阅读下面的短文，文中有15处空白，每处空白给出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。 One of the most important technological developments during the 1980s has been the emergence of optical fiber communication as a major international industry. One indication of the{{U}} (51) {{/U}}of this development is the total{{U}} (52) {{/U}}of installed fiber, which was estimated to be 3.2 million kilometers in the U.S. alone by the end of 1987. Over 90% of this fiber was placed.{{U}} (53) {{/U}}during the time period of 1982—1987. Long-haul trunk installations(长途干线设施) have dominated,{{U}} (54) {{/U}}for about 95% of the fiber in the U.S. In the early 1950s the researchers who produced the first clad glass optical fibers were not{{U}} (55) {{/U}}of using them. for communications.{{U}} (56) {{/U}} , fiber optics was already a well-established commercial technology when the famous paper by Kao and Hockham,{{U}} (57) {{/U}}the use of low-loss optical fibers for communication, appeared in 1966. The first low-loss silica fiber was described in a publication which appeared in October of 1970. The date of this publication is sometimes{{U}} (58) {{/U}} as the beginning of the era of fiber communication. Although this development did receive{{U}} (59) {{/U}}attention in the research community at- the time, it was far from inevitable that a major industry would evolve. The technological barriers appeared{{U}} (60) {{/U}}because there were serious doubts as to{{U}} (61) {{/U}}these fiber components could ever be produced economically enough, but the market potential was very significant.{{U}} (62) {{/U}}, research and development activity expanded rapidly, and a number of important issues were{{U}} (63) {{/U}}during the early 1970s. During the middle and late 1970s, the rate of progress towards marketable products accelerated as the emphasis {{U}}(64) {{/U}}from research to engineering. Fibers with losses approaching the Payleigh limit of 2 dB/km at a wavelength of 0.8um were produced. By 1980 improvement in component performance, cost, and reliability led to major commitments{{U}} (65) {{/U}}the part of telephone companies.