2. 考研
  3. Learning disabilities are very common. They affect perhaps 10 percent of all children. Four times as many boys as girls have lea

Learning disabilities are very common. They affect perhaps 10 percent of all children. Four times as many boys as girls have lea

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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 the 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.
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 文章第四段中讲到：研究人员通过检查一个无学习能力者的大脑，他们发现了两种不寻常的现象。一种与控制语言的脑左半部细胞有关。通常情况下，这些细胞为白色。然而，被研究的无学习能力者的大脑此处却是灰色的。研究人员还发现，许多神经细胞并不是按照它们应有的方式排列成行，这些神经细胞是混在一起的。可见差异在于脑细胞的颜色和排列。所以应该选D。
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