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Neuroscientists have explained the risky, aggressive or just plain baffling behavior of teenagers as the product of a brain that is somehow compromised. Groundbreaking research in the past 10 years, however, shows that this view is wrong. The teen brain is not defective. It is not a half-baked adult brain, either. It has been forged by evolution to function differently from that of a child or an adult.
The most important of the teen brain's features is its ability to change in response to the environment by modifying the communication networks that connect brain regions. It allows teenagers to make enormous progress in thinking and socialization. But the change also makes them sensitive to dangerous behavior and serious mental disorders.
The most recent studies indicate that the riskiest behaviors arise from a mismatch between the maturation of networks in the limbic system(边缘系统), which drives emotions at adolescence, and the maturation of networks in the prefrontal cortex（前额皮质）, which occurs later and promotes sound judgment and the control of impulses. Indeed, we now know that one's prefrontal cortex continues to change noticeably until his 20s. And yet adolescence seems to be starting earlier, extending the “mismatch years.”
The plasticity of networks linking brain regions—and not the growth of those regions, as previously thought—is key to eventually behaving like an adult. Understanding that, and knowing that a widening gap between the development of emotional and judgment networks is happening in young people today, can help parents, teachers, counselors and teenagers themselves. People will better see that behavior such as risk-taking and turning away from parents and toward peers are not signs of cognitive or emotional problems. They are a natural result of brain development, a normal part of adolescents learning how to negotiate with a complex world.
The same understanding can also help adults decide when to intervene. A 15-year-old girl's departure from her parents' tastes in clothing, music or politics may be a source of anxiety for Mom and Dad but does not indicate mental illness. A 16-year-old boy's tendency to skateboard without a helmet or to accept risky dares from friends is not unimportant but is more likely a sign of short-range thinking and peer pressure than a desire to hurt himself. Knowing more about the unique teen brain will help all of us learn how to separate unusual behavior that is age-appropriate from that which might indicate illness. Such awareness could help society reduce the rates of teen addiction, motor vehicle accidents and depression.
42.The underline word in the paragraph possibly means not_____.
A. disable B. enormous C. mature D. perfect
43.The second paragraph is mainly about______.
A. brain's B. changes of teen brain's
B. acts of brain changes D. effects brain change can
44.The limbic system and the prefrontal cortex are mentioned in paragraph 3 to______.
A.show the differences between them
B.explain what leads to teens' riskiest behavior
C.explain the relationship between early adolescence and them
D.show how the mismatch between their maturation of networks happens
42.【答案】A
【解析】词义猜测。根据第一段第一、 二句Neuroscientists have explained the risky, aggressive or just plain baffling behavior of teenagers as the product of a brain that is somehow compromised. Groundbreaking research in the past10 years, however, shows that this view is wrong.神经科学家已经解释了青少年的冒险、好斗或仅仅是莫名其妙的行为举动，他们的很多行为常常令人大惑不解。神经科学家们曾一度认为这是大脑受损的结果。然而,过去十年间的突破性研究表明这一观点是错误的。和最后二句It is not a half-baked adult brain, either. 这也不是半成熟的成人大脑。It has been forged by evolution to function differently from that of a child or an adult.它是由进化锻造产生的以不同于儿童或成人的方式运作的。可知,青少年大脑并非存有缺陷,也不是尚未成熟的成人大脑。划线词的意思应该是残疾的,故答案为A。Disable
43.缺
44.【答案】C
【解析】推理判断。根据第三段中Indeed, we now know that one's prefrontal cortex continues to change noticeably until his 20s. And yet adolescence seems to be starting earlier, extending the mismatch years.实际上,我们现已知道人类的前额皮质直到20多岁还在不断发生显著变化。而如今,青春期似乎越来越提前,使得这段“不一致时间”比以前更长。由此可知,在第3段提到了边缘系统和前额叶皮层是为了解释青春期早期与他们之间的关系。故答案为C。
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