2024年b类初试真题试卷及参考答案

更新时间: 试题数量: 购买人数: 提供作者:

有效期: 个月

章节介绍: 共有个章节

收藏
搜索
题库预览
Autism is a neurological disorder that usually appears before a child’s third birthday. It is marked by impaired language skills, impaired social skills, and repetitive behaviors. Recently there has been a dramatic and unexplained increase in the number of children diagnosed with autism. Medical scientists estimate an autism ratio of 1 in every 150 children in the United States; others estimate 1 in 500. Both figures are alarming, especially considering that scientists do not know what causes autism and how to cure it. Medical researchers have been looking for answers. (51) ______ At one extreme of the spectrum, individuals are severely affected, while at the other extreme, individuals are only mildly affected. Some individuals cannot speak; others are highly verbal. Some are overly sensitive to noise; others seem not to notice it. Some prefer to be alone; others want friends. Some even marry and have children. Some are unable to learn school subjects; others go on to acquire a Ph.D. degree. Indeed, each person with autism may have a unique set of traits. (52) ______ In the 1950s, autism was considered a psychological disorder, caused by “refrigerator mothers”. Their personalities were thought to be so cold and uncaring that their children grew up unable to speak or interact with others. As research progressed, scientists realized that autism was actually a neurological, or brain, disorder. Studies have identified several areas of the brain that differ from the norm in autistic individuals. These areas involve emotions, critical thinking, learning, and paying attention. However, no one area seems to hold the key to autism. Some researchers have inferred that faulty neural connections between areas of the brain may be responsible for autism. Or perhaps there are too many connections, resulting in an overload of messages within the brain. (53) ______ In a recent study, researchers took blood samples from many newborns. When some of these babies later developed autism, the researchers tested their early blood samples and found high levels of four chemicals that influence the early phases of brain development. However, they have not been able to prove a direct link between the chemicals and the autism. There is strong agreement that genes, carriers of inherited traits, play a role in autism, and research continues to explore heredity as a cause. Recently, researchers found a link between autism and the age of the child’s father, with the odds of parenting an autistic child increasing with older fathers. It is also known that among autistic children, males predominate by a ratio of 4 to 1, and that autism seems to run in families. Despite the strong hereditary evidence, scientists have yet to identify a single gene responsible for autism. They now think that a combination of 10 or more faulty genes may trigger autism. (54) ______ They have looked into toxic metals in water and soil, harmful chemicals in household products, viruses, air pollution, and even television viewing, but have not found a consistent link to autism. (55) ______ However, treatment, either through medication or training, has benefited many autistic children by helping them to relax, to constrain antisocial behavior, to participate socially, and