2. 职称英语
  3. Learning disabilities are very common. They affect perhaps 10 percent of all

Learning disabilities are very common. They affect perhaps 10 percent of all

游客2025-03-21  48
问题     Learning disabilities are very common. They affect perhaps 10 percent of all children. Four times as many boys as girls have learning disabilities.
    Since about 1970, new research has helped brain scientists understand these problems better. Scientists now know there are many different kinds of learning disabilities and that they are caused by many different things. There is no longer any question that all learning disabilities result from differences in the way the brain is organized.
    You cannot look at a child and tell if he or she has a learning disability. There is no outward sign of the disorder. So some researchers began looking at the brain itself to learn what might be wrong.
    In one study, researchers examined the brain of a learning-disabled person, who had died in an accident. They found two unusual things. One involved cells in the left side of the brain, which control language. These cells normally are white. In the learning-disabled person, however, these cells were gray. The researchers also found that many of the nerve cells were not in a line the way they should have been. The nerve cells were mixed together.
    The study was carried out under the guidance of Norman Geschwind, an early expert on learning disabilities. Doctor Geschwind proposed that learning disabilities resulted mainly from problems in the left side of the brain. He believed this side of the brain failed to develop normally. Probably, he said, nerve cells there did not connect as they should. So the brain was like an electrical device in which the wires were crossed.
    Other researchers did not examine brain tissue. Instead, they measured the brain’s electrical activity and made a map of the electrical signals.
    Frank Duffy experimented with this technique at Children’s Hospital Medical Center in Boston. Doctor Duffy found large differences in the brain activity of normal children and those with reading problems. The differences appeared throughout the brain. Doctor Duffy said his research is evidence that reading disabilities involve damage to a wide area of the brain, not just the left side. [br] Scientists found that the brain cells of a learning-disabled person differ from those of a normal person in______.
选项 A、structure and function
B、color and function
C、size and arrangement
D、color and arrangement
答案 D
解析 本题是一道具体细节题。问科学家发现有学习缺陷的人的脑细胞与正常人的在哪些方面不同。文章第四段指出，在一种试验中，研究者检验在事故中丧生的学习上有缺陷的人的大脑，他们有两个异常发现：(1)大脑的左半球控制着语言能力，左半球的脑细胞应该是白色的，但是，有学习缺陷的人的左半球的脑细胞却是灰色的；(2)在有学习缺陷的人的大脑中，许多脑细胞不是像正常细胞一样呈线状排列的，而是团在一起的。因此，本题的正确答案应是D“颜色与排列方式不同”。
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