单选题23. It was not until he entered the airport ______ he realized that he had forgotten to bring his air ticket with him.
单选题. Gallaudet University currently does not allow students to keep pets in their dorm rooms 21 are made only for service animals such as guide dogs and hearing dogs. These 22 dogs provide services that benefit their student owners. But other kinds of pets can be 23 to students too. Pets should be allowed to live in the dorms because they can help students 24 stress and learn responsibility. College life is very 25 and students often feel a lot of pressure and 26 . Pets could help students relieve 27 in many ways. For example, playing with pets could give students a study break. Walking a dog or playing with a cat would allow the students to relax their body and 28 . When the students return to their studying, they would feel 29 and ready to work again. Pets could also relieve social stress or homesickness. A dog or cat could provide 30 and affection when students have problems with their friends or 31 home. Sometimes it is easier to talk to a pet than to a person. Talking about problems helps students figure out 32 . Pets would have a positive influence on the stress of college life. College is also a time when students need to learn to be responsible. 33 pets could help students learn responsibility in several ways. 34 , pets need to be fed and watered on a regular schedule. Some pets also need to be taken out 35 others need their litter box or cage cleaned. Students would learn to schedule time for these 36 between their classes and activities. New students 37 having their parents do things for them. But parents do not live 38 college campuses with their children. Therefore, caring for a pet is something students would have to do 39 . They would learn how to solve problems on their own and how to follow through with their commitments. Having pets would teach students to 40 more adult responsibilities.21.
单选题 Culture is activity of thought
单选题11. My approach is not to learn everything about something, but ______ something about everything.
单选题7. Taj Mahal in India is perhaps one of the most beautiful buildings in the world, where I spent ______ moonlit night.
单选题 Such ______ the case
单选题12. The twelve constellations located along or near the ecliptic ______ the signs of the zodiac.
单选题26. ______, the box will break into pieces.
单选题28. The development of mechanical timepieces spurred the search for more accurate sundials ______.
单选题. Synchronized Sex 性的同步 by Menno Schilthuizen When the biological clocks of males and females are out of sync, their sex lives suffer. Or at least it does if they are melon flies, Japanese entomologists have found. They say that differences in daily rhythms might even promote the evolution of new species. Takahisa Miyatake and Toru Shimizu of Okinawa Prefectural Agricultural Experimental Station made their discovery while studying the melon fly Bactrocera cucurbitae, a notorious pest of melons, couregttes and other members of the gourd family. By selective breeding from flies that were quickest to mature and mate, they built up a population of fast developing individuals. In a similar way, they also bred a line of slow developers. After 25 generations, the slow developers' larvae took more than 12 days to mature, while the fast developers matured in just 6 days. To their surprise, Miyatake and Shimizu noticed that this was not the only difference between the two lines. In nature, the melon flies mate around dusk. But among the fast developers, sexual activity peaked in late afternoon, one hour before dusk, while the slow developers only started getting interested in sex around three-and-a-half hours after nightfall. "Apparently, both rhythms are regulated by the same clock gene," says Miyatake. To see how this would influence the ability of the slow and the fast lines to crossbreed, the researchers marked flies from both lines, put them together in cages, and watched to see which mated with expected, which as most matings took place between males and females from the same line. The finding, which will be reported in the journal Evolution, suggests that differences in body clocks could cause new species to evolve. Miyatake says the behaviour of some species suggest they may have arisen this way. "Many closely related species of insect differ in their daily mating time," he says. "For example, the only thing that separates two other flies, Bactrocera tryoni and bactrocera neohumeralis, is the fact that the former mates at dusk, the latter in the daytime." "This is interesting work," says Jeffrey Feder, an evolutionary geneticist who studies fruit flies at the University of Notre Dame in Indiana. "It is very exciting that Miyatake and Shimizu have shown how selection on the larvae can affect the mating pattern in adults and prevent crossbreeding." Feder agrees that the effect could be important in the evolution of new species, especially when insects undergo a shift in lifestyle. For example, if a population of flies starts feeding on a new fruit that rots quickly, this could select for fast-developing larvae with a different mating time and which would not breed with the ancestral stock. "This is getting at the heart of what Darwin was saying in On the Origin of Species," says Feder.11. It can be inferred from the first paragraph that ______.
单选题18. The police chief announced that he would soon inquire ______ the deaths of two young girls.
单选题. The Brain and the Computer 大脑与计算机 Considering that the brain can be compared to the electronic computer, it may be useful to ask if one computer, the brain, has any advantages over the other, the electronic computer. First, compare the amount of energy needed to operate the brain and that needed to run a computer. It has been calculated that the entire brain runs on very little energy as compared with a machine. A machine with as great a capacity as the brain—assuming one could be built—would need at least one million times as much electrical power to continue operating. But the computer is a faster worker than the brain. The advanced calculators are thousands upon thousands of times faster than the brain, and models yet to be built will probably be yet speedier. Memory is of great importance in "Computer-type" operations. The number of bits of information that can be stored determines the ability of the system to do complex operations. The more bits stored, the more complex the calculations that can be made. In 1962, advanced electronic computers could store about 40,000 bits of information. Here, the brain shows its distinct advantages: although the number of bits stored is certainly not known, it has been estimated at many millions of bits. One specialist has said that to build a machine to imitate the capacity of the human brain, it would be necessary to make it the size of a very tall building. "The brain is like a computing machine, but there is no computing machine like the brain." Humans, however, may not continue to have this superiority in the future. Recent developments in electronic equipment, for example, Sceptron, have rapidly changed our ideas. Each Sceptron is extremely small, which may mean that is will soon be possible to make a calculator as complex as the human brain—with the same bit storage capacity—and be able to fit it neatly in a desk. There is one great and very important distinction between humans and machines. While electronic devices may think, "hunger" for electricity, and in other ways imitate animal and human behavior, men have desires, hungers, thirsts, and a complex existence of which the brain is a major, but not the entire, aspect. Human hopes and fears are not like those of the electronic mechanisms, nor will they be so long as we continue to construct thinking machines whose function is only to think as they are programmed. The use that man makes of automation, decision-making machines, and the other results of cybernetics is dependent on man himself. As Norbert Wiener states in his book The Human Use of Human Beings mankind is faced with two possible destructive directions in which cybernetics could develop, influencing all of society. One is that machines that do not learn will obey all instructions and never vary in their approach to problems. The other is that man may find himself in the position of someone who has released an angry force. Machines that can learn and make decisions on the basis of their learning are not obligated to decide in ways that please or improve humanity. Men cannot give machines responsibility for mankind; final choices must always be made by, and in favor of, men.1. The energy needed to operate the human brain is ______ that needed to run a computer.
单选题 We thought she'd come just for a visit
单选题 Everybody knows that the earth is spherical
单选题 You think that everyone should be equal
单选题5. We all think ______ that the football match has been cancelled.
单选题. It's the Solution 这就是解决问题的方法 by Nell Boyce human eggs don't freeze well—or so IVF specialists have always thought. But biologists in New Jersey now say they have overcome the problem , by abandoning the idea that eggs should be frozen in a solution that resembles body fluids. The researchers have obtained high survival rates after cryopreserving and then thawing mouse eggs. If their technique also works with human eggs, then women whose eggs are frozen—before they undergo chemotherapy that damages their ovaries, for example—will have a better chance of becoming mothers. Fertility centres routinely freeze sperm and embryos, but only a few births have been reported using frozen eggs. James Stachecki of the Institute for Reproductive Medicine and Science of St. Barnabas Medical Center in West Orange, New Jersey, wondered if the saline solution sued to freeze eggs was to blame. Cells must be surrounded by a more concentrated solution during freezing. This pulls water out of the cells by osmosis and reduces the chances of ice crystals forming, which can damage cell structures. Cryobiologists usually use a saline designed to mimic body fluids. But Stachecki suspected that sodium ions from such solutions were getting into the eggs and poisoning them. Instead, he decided to try a solution containing choline ions, which do not readily cross cell membranes. Choline is an organic molecule found in many plant and animal tissues, and is a constituent of B-complex vitamins. Cryopreservation experiments on other types of cells using choline solutions had produced promising results. Using hundreds of mouse eggs, Stachecki and his colleagues found that the choline solution allowed 90 percent to survive freezing and thawing. And when the surviving eggs were fertilized, 60 percent developed into the ball of cells called a blastocyst. "The results are very encouraging," says Rogery Gosden, a reproductive biologist at the University of Leeds. With conventional saline, only 50 percent of eggs survived freezing and just 10 percent of those fertilized went on to form a blastocyst. "The plan now is to do more work in humans to test how well it works," says Stachecki. Several women have already volunteered to donate their eggs for the research. If the new technique works for humans, it may allow easier egg banking at fertility clinics.6. New Jersey biologists differ from IVF specialists in that ______.
单选题 The medical record shows that it was the drug
单选题. Surgeons of the Future Will be Robots Injected into Your Body 未来的外科医生是注射到人体内的机器人 Tiny crew members inside a microscopic submarine are injected into your bloodstream for an incredible mission that will take them deep inside your body to perform delicate surgery! It sounds like the science fiction plot for the 1966 movie "Fantastic Voyage", but this amazing scenario is close to becoming science fact—Japanese researchers are designing "microrobots" that will battle illnesses from inside human organs. "The microrobots are almost like shrunken men, zipping around through the veins to destroy cancer or repair damaged tissue," explained Kenzo lnagaki, a deputy director of Japan's Ministry of International Trade and Industry—which is putting up a staggering $170 million for the project. The ground-breaking undertaking will begin in April. It will give doctors the ability to fight diseases in areas of the human body that were previously unreachable except by surgery, says Hiroyuki Fujita, a spokesman for the fantastic project that will involve six universities and giant companies like Toyota, Hitachi, Nikon and Toshiba. Researchers estimate it will take 10 years to carry out the plan, but they say that when it's completed it will dramatically change medicine as we know it! One robot they are planning is a "small pill"—a submarine-shaped capsule you swallow that can be guided to a diseased area inside your body. "It will be about two-fifths of an inch in diameter, and enclose a tiny robot," said Fujita. "In fact, the submarine' would be an incredibly tiny lab able to analyze conditions within the body." Once it enters the stomach, the robot could be steered either by an external remote control or by a built-in guidance system. When it reached a diseased area, the robot would be able to diagnose a condition close up and treat it with just the right amount of medication. "Once it has served its purpose, the pill will harmlessly exit the body through the waste system," he said. A second robotic device is a "micro-intelligent catheter" about one-fifth of an inch in diameter. The catheter, a tube withy a camera and a laser on the end, could be threaded into the gallbladder and pancreas. "Its tiny size will eliminate much of the pain and discomfort experienced by today's patients when much larger catheters are used," he said. "The probe will send doctors an accurate picture of what is happening inside without surgery." And its laser tip will enable physicians to operate internally. "Doctors will be able to use it to cut away cancerous growth, destroy blood clots or to repair breaks in the tissue," said Fujita. Ironically, these tread-setting medical developments planned by the Japanese come from research started years age in the Massachusetts Institute of Technology in the US—but these efforts faltered because of a lack of funding.6. "Tiny crew members" in the first paragraph refers to ______.
单选题23. ______ in an atmosphere of simple living was what her parents wished for.