| 考博易错题（2018/12/26） |
| 第1题： The motorist had to ______ to avoid knocking the old woman down in the middle of the road. A．swerve B．twist C．depart D．swing |
| 【单选题】： |
| 第2题：Famed singer Stevie Wonder can’t see his fans dancing at his concerts. He can’t see the hands of his audience as they applaud wildly at the end of his Superstition. Blind from birth, Wonder has waited his whole life for a chance to see. Recently, Wonder visited Mark Hamayan, a vision specialist. He thought that a new device currently being studied by Humayan might offer him that chance. The device, a retinal prosthesis, is a tiny computer chip implanted inside a patient’s eye. The chip sends images to the brain and allows some sightless people to see shapes and colors. Wonder hoped the retinal prosthesis might work for him. "I’ve always said that if ever there’s possibility of my seeing," said Wonder, "then I would take the challenge." Unfortunately for Wonder, that challenge will have to wait. Humayan explained that the device isn’t ready for people who have been blind since birth. Their brains may not be able to handle signals from a retinal prosthesis because their brains have never handled signals from a healthy eye. The retinal prosthesis and other devices, however, show great promise in helping many other sightless people who once had vision see again. Perhaps one day soon, some formerly sightless people may be in Wonder’s audience looking up—and seeing him—for the very first time. Wonder’s willingness to take part in retinal prosthesis studies and the results of those studies are giving new hope to people who thought they would be blind for the rest of their lives. More than one million people in the United States are considered legally blind, meaning that their eyesight is severely impaireD、Another one million are totally blinD、 Two types of specialized cells in the retina—rods and cones—are critical for proper vision. Light enters the eye and falls on the rods and cones in the retinA、Those cells convert the light to electrical signals which travel through the optic nerve to the brain. The brain interprets those signals as visual images. Rods detect light at low levels of illumination. For instance, rods allow you to see faint shadows in dim moonlight.Cones, on the other hand, are most sensitive to color. Some diseases can damage cells in the retinA、For instance, macular degeneration causes blindness and other vision problems in 700,000 people in the United States each year. The condition is caused by a lack of adequate blood supply to the central part of the retinA、Without blood, the rods, cones, and other cells in the retina die. Devices such as the retinal prostheses won’t prevent or cure our eye diseases, but they may help patients who have eye disorders regain some of their vision.Different forms of retinal prostheses are currently being developeD、On one type, a tiny computer chip is embedded in the eye. The chip has a grid of about 2,500 light-sensing elements called pixels. Light entering the eye strikes the pixels, which convert the light into electrical signals. The pixels then send the electrical signals to nerve cells behind the retinA、Those cells send signals via the optic nerve to the brain for interpretation. Many people who have had a retinal prosthesis implanted say they can see shapes, colors, and movements that they couldn’t see before. "It was great," said HaroldChurchey, who received his retinal prosthesis 15 years after he became totally blinD、"To see light after so long—it was just wonderful. It was just like switching a light on." (572 words.Current Science.April 7, 2000) Why does macular degeneration cause blindness and other vision problemsA．Macular degeneration causes improper interpretation by the brain. B．Macular degeneration makes the retina less sensitive to the light. C．Macular degeneration changes the functions of rods and cones. D．Macular degeneration is the result of inadequate supply of blood in the retinA、 |
| 【单选题】： |
| 第3题： The Iargcst single source of man-made radiation is medical X rays, yet most scientists agree that hazards from this source are not as great as those from weapons test fallout, since strontium 90 and carbon 14 become incorporated into the body, hence delivering radiation for an entire life- time. The issue is, however, by no means uncontroversial; the last two decades have witnessed intensified examination and dispute about the effects of low-level radiation, beginning with the United Nations ScientificCommittee on theEffects ofAtomic Radiation, which reported in 1958: "Even the smallest amounts of radiation are liable to cause deleterious genetic and perhaps also somatic effects." A、survey conducted inBritain confirmed that an abnormally high percentage of patients suffering from arthritis of the spine who had been treated with X rays contracted cancer.Another study revealed a high incidence of childhood cancer in eases where the mother had been given prenatal pelvic X rays. These studies have pointed to the need to reexamine the assumption that exposure to low-linear energy transfer presents only a minor risk. Recently, examination of the death certificates of former employees of a WestCoast plant which produces plutonium for nuclear weapons revealed markedly higher rates for cancers of the pancreas, lung, bone marrow, and lymph systems than would have been expected in a normal population. While the NationalAcademy of SciencesCommittee attributes this difference to chemical or other environmental causes rather than radiation, other scientists maintain that any radiation expo- sure, no matter how small, leads to an increase in cancer risk. It is believed by some that a dose of one rem, if sustained over many generations, would lead to an increase of 1 percent in the number of serious genetic defects at birth, a possible increase of 1,000 disorders per million births. In the meantime, regulatory efforts have been disorganized, fragmented, inconsistent, and characterized by internecine strife and bureaucratic delays.A、Senate report concluded that coordination of regulation among involved departments and agencies was not possible because of jurisdictional disputes and confusion. One federal agency has been unsuccessful in its efforts to obtain sufficient funding and manpower for the enforcement of existing radiation laws, and the chairperson of a panel especially created to develop a coordinated federal program has resigneD、 |
| 第4题： Applied research, undertaken to solve specific practical problems, has an immediate attractiveness because the results can be seen and enjoyeD、For practical reasons, the sums spent on applied research in any country always far exceed those for basic research, and the proportions are more unequal in the less developed countries. Leaving aside the funds devoted to research by industry--which is naturally far more concerned with applied aspects because these increase profits quickly--the funds the U.S. Government allots to basic research currently amount to about 7 percent of its overall research and development funds. Unless adequate safeguards are provided, applied research invariably tends to drive out basiC、Then, asDr. Waterman has pointed out, "Developments will inevitably be undertaken prematurely, career incentives will gravitate strongly toward applied science, and the opportunities for making major scientific discoveries will be lost. Unfortunately, pressures to emphasize new developments, without corresponding emphasis upon pure science tend to degrade the quality of the nation’s technology in the long run, rather than to improve it." |
| 第5题： The helmets are designed to ______ impacts equivalent to a fall from a bicycle. A．withhold B．withstand C．withdraw D．wither |
| 【单选题】： |