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text 3 earthquake survivors trapped in rubble could one day be saved by an unlikely rescuer：a robotic caterpillar that burrows its way through debris. just a few centimeters wide， the robot relies on magnetic fields to propel it through the kind of tiny crevices that would foil the wheeled or tracked search robots currently used to locate people trapped in collapsed buildings. the caterpillar’s inventor， norihiko saga of akita prefectural university in japan， will demonstrate his new method of locomotion at a conference on magnetic materials in seattle. in addition to lights and cameras， a search caterpillar could be equipped with an array of sensors to measure other factors—such as radioactivity or oxygen levels—that could tell human rescuers if an area is safe to enter. to make the caterpillar move forwards， saga moves a magnetic field backwards along the caterpillar. inside the caterpillar’s “head” capsule， magnetic fluid surges towards the attractive magnetic field， causing the capsule to bulge out to the sides and draw its front and rear portions up. as the magnetic field passes to the next capsule， the first breaks free and springs forward and the next capsule bunches up. in this way， the caterpillar can reach speeds of 4 centimeters per second as it crawls along. moving the magnetic field faster can make it traverse the caterpillar before all the capsules have sprung back to their original shapes. the segments then all spring back， almost but not quite simultaneously. saga plans to automate the movement of the caterpillar by placing electromagnets at regular intervals along the inside of its polymer tube. by phasing the current flow to the electromagnets， he’ll be able to control it wirelessly via remote control. he also needs to find a new type of rubber for the magnetic capsules， because the one he’s using at the minute eventually begins to leak. but crawling is not the most efficient form of locomotion for robots， says robert full of the university of california at berkeley， an expert in animal motion who occasionally advises robotics designers. “if you look at the energetic cost of crawling， compared to walking， swimming or flying， crawling is very expensive，” he says. walking， on the other every step， energy is conserved in the foot and then released to help the foot spring up. saga acknowledges this inefficiency but says his caterpillar is far more stable than one that walks， rolls on wheels or flies. it has no moving parts save for a few fluid-filled rubber capsules. biped robots and wheeled robots require a smooth surface and are difficult to miniaturize， and flying robots have too many moving parts. “my peristaltic crawling robot is simple—and it works，” he says. 31. from this passage， we can learn that [a] a robotic caterpillar can crawl by a pair of rubber rods [b] when a caterpillar moves， the magnetic field moves backwards along it [c] the environment couldn’t influence a robotic caterpillar’s guts， which are wrapped in a capsule [d] crawling is very stable and efficient， and when it moves， only a few elements are needed 32. according to this passage， which is not true about the construction of the robotic caterpillar？ [a] a robotic caterpillar is made from a series of rubber capsules filled with a magnetic fluid. [b] iron particles， water， and a detergent-like surfactant form a magnetic fluid. [c] each capsule filled with a magnetic fluid is linked to a pair of rubber rods. [d] in order to keep stable condition， the caterpillar’s guts are wrapped in a clear， flexible polymer tube. 33. the meaning of the word “peristalsis” in paragraph three is similar to. [a] swimming [b] flying [c] crawling [d] walking 34. comparing the robotic caterpillar and the other robots， which of the following is not true？ [b] flying robots are very inconvenient when moving， because they have too many moving parts. [c] the robotic caterpillar only has rubber capsules filled with a magnetic fluid. [d] it’s incapable for wheeled robots to locate trapped people because they are impossible to miniaturize. 35. the passage is mainly about [a] why a robotic caterpillar can find trapped people [b] how a robotic caterpillar work [c] the instruction of the magnetic caterpillar [d] how a robotic caterpillar peristalsis text 4 when a disease of epidemic proportions rips into the populace， scientists immediately get to work， trying to locate the source of the affliction and find ways to combat it. oftentimes， success is achieved， as medical science is able to isolate the parasite， germ or cell that causes the problem and finds ways to effectively kill or contain it. in the most serious of cases， in which the entire population of a region or country may be at grave risk， it is deemed necessary to protect the entire population through vaccination， so as to safeguard lives and ensure that the disease will not spread. the process of vaccination allows the patient’s body to develop immunity to the virus or disease so that， if it is encountered， one can ward it off naturally. to accomplish this， a small weak or dead strain of the disease is actually injected into the patient in a controlled environment， so that his body’s immune system can learn to fight the invader properly. information on how to penetrate the disease’s defenses is transmitted to all elements of the patient’s immune system in a process that occurs naturally， in which genetic information is passed from cell to cell. this makes sure that， should the patient later come into contact with the real problem， his body is well equipped and trained to deal with it， having already done so before. there are dangers inherent in the process， however. on occasion， even the weakened version of the disease contained in the vaccine proves too much for the body to handle， resulting in the immune system succumbing， and， therefore， the patient’s death. such is the case of the smallpox vaccine， designed to eradicate the smallpox epidemic that nearly wiped out the entire native american population and killed massive numbers of settlers. approximately 1 in 10，000 people who receives the vaccine contract the smallpox disease from the vaccine itself and dies from it. thus， if the entire population of the united states were to receive the smallpox vaccine today， 3000 americans would be left dead. fortunately， the smallpox virus was considered eradicated in the early 1970s， ending the mandatory vaccination of all babies in america. in the event of a re-introduction of the disease， however， mandatory vaccinations may resume， resulting in more unexpected deaths from vaccination. the process， which is truly a mixed blessing， may indeed hide some hidden curses. 36.the best title for the text may be [a] “vaccinations： a blessing or a curse” [b] “principles of vaccinations” [c] “vaccines： methods and implications” a)sq_=NyOA&�2Y?/R[ 本_资_料_来_源_于_贵_州_学_习_网 考研一方考研英语 Http://wwW.gzU521.coM )a)sq_=NyOA&�2Y?/R [d] “a miracle cure under attack” 37.what does the example of the smallpox vaccine illustrate？ [a] the possible negative outcome of administering vaccines. [b] the practical use of a vaccine to control an epidemic disease. [c] the effectiveness of vaccines in eradicating certain disease. [d] the method by which vaccines are employed against the disease. 38.the phrase “ward it off naturally” （paragraph 2） most probably means [a] dispose of it naturally [b] fight it off with ease [c] see to it reluctantly [d] split it up properly 39.which of the following is true according to the text？ [a] saving the majority would necessarily justify the death of the minority. [b] the immune system can be trained to fight weaker versions of a disease. [c] mandatory vaccinations are indispensable to the survival of the populace. [d] the process of vaccination remains a mystery to be further resolved. 40.the purpose of the author in writing this passage is [a] to comment and criticize [b] to demonstrate and argue [c] to interest and entertain[d] to explain and inform part b directions： in the following text， some sentences have been removed. for questions 41-45， choose the most suitable one from the list a-g to fit into each of the numbered blanks. there are two extra choices， which do not fit in any of the blanks. mark your answers on answer sheet 1. （10 points） we are seeing a series of paradoxes at the turn of the millennium. on the one hand， globalization means that national frontiers are becoming increasingly meaningless， but on the other， we are being swept by a wave of parochialism， with countries clinging to the notion of sovereignty.41）but there are so many factors in the world that make this position increasingly meaningless. governments no longer have complete control over their economic and monetary policies， and many multinationals now have greater profits than individual country’s gdp. the end of the cold war has brought its own dangers and we need to find a new balance of power in the world. it has also spawned many conflicts. governments must be prepared to surrender some authority to global and regional institutions or we risk world disorder. it is tragic that， just when we need a strong international organization， the united nations is starved of funds and often sidelined by its own member states. what happened in east timor was unforgivable because it was foreseeable. angola has been another sad instance of international vacillation. 42） i do think world war is less likely for the present， although i worry about the proliferation of nuclear weapons at one end and lethal small arms at the other. 43） another worry stems from the huge economic imbalances in a world where the richest 20 per cent have 86 per cent of global gdp， and the 20 poorest countries only one per cent. humanitarian aid is no more than a palliative. 44）the international implications of， for example， the collapse of africa are unthinkable. there must be a new concept of security based not just on military and defense matters but on economic and social concerns too. 45） the global pendulum has swung too far towards a total dependence on market forces， but finding some point of balance in the middle is extremely difficult. i am by nature optimistic， but in my gloomier moments i sometimes think the only solution will be an invasion from outer space-then at last everyone would unite！ ［a］as long as more than a million people continue to live in direct poverty we can never hope to achieve national or international stability. ［b］we need an international body with teeth-morally and in action. perhaps the un should be given its own force. ［c］ many members of the un have only become nation states in the last few decades， so i can understand why they are so keen to hang on to their independence. ［d］it is terrifying the way that power is increasingly disseminated to small， completely ruthless groups like terrorists， drug traffickers and local warlords. the great imponderable is that some nut could create a nuclear explosion. or that some essentially local conflict could escalate out of control. you cannot isolate instability： it gets exported.$R .:?sN7}?{:�ga[转 贴 于 我 的 学 习 网 考研一方考研英语 HTtp://wwW.gzU521.coM)$R .:?sN7}?{:�ga ［e］the mainly purpose of founding the united nations is preventing aggressions and wars. it is hard to attribute the success to the united nations although no new world war broke out since its establishment. the united nations is always helpless of preventing the regional wars. ［f］the notion of sovereignty is more and more strong while the influence of the united nations is weaker and weaker. ［g］western countries must increase their development aid programmes， not out of charity but for reasons of self-interest.   |
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