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.
Doctor Duffy believed that______.

选项 A、he found the exact cause of learning disabilities
B、the problem of learning disabilities was not limited to the left side of the brain
C、the problem of learning disabilities resulted from the left side of the brain
D、the problem of learning disabilities did not lie in the left side of the brain

答案B

解析 文章在最后一段中论述了达菲医生的观点。达菲医生对那些无学习能力的儿童进行了研究。通过研究证实,无学习能力与大脑许多范围区域的损伤有关,不仅仅是大脑的左半部。可见,达菲医生认为,无学习能力不只是与大脑的左半部有关。B项符合文意。A、C、D项的内容都与原文所述不符。所以本题的正确答案为B。
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