Doctors are starting to find more and more information that suggests a connection between exercise and brain development. Judy Cameron, a scientist at Oregon Health and Science University, studies brain development. According to her research, it seems that exercise can make blood vessels, including those in the brain, stronger and more fully developed. Dr. Cameron claims this allows people who exercise to concentrate better. As she says: "While we already know that exercise is good for the heart, exercise can literally cause physical changes in the brain."
The effects of exercise on brain development can even be seen in babies. Babies who do activities that require a lot of movement and physical activity show greater brain development than babies who are less physically active. With babies, even a little movement can show big results. Margaret Barnes, a pediatrician (儿科医师), believes in the importance of exercise. She thinks that many learning disabilities that children have in elementary school or high school can be traced back to a lack of movement as babies. "Babies need movement that stimulates their five senses. They need to establish a connection between motion and memory. In this way, as they get older, children will begin to associate physical activity with higher learning," says Margaret.
Older people can beef up their brains as well. Cornell University studied a group of seniors ranging in age from seventy to seventy-nine. Their study showed a short-term memory increase of up to 40 percent after exercising just three hours a week. The exercise does not have to be very difficult, but it does have to increase the heart rate. Also, just like the motion for infants, exercise for older people should involve some complexity. Learning some new skills or motions helps to open up memory paths in the brain that may not have been used for a long time.
For most people, any type of physical activity that increases the heart rate is helpful. The main goal is to increase the brain"s flow of blood. And your brain can benefit from as little as two to three hours of exercise a week.
单选题
Research by Dr. Cameron seems to suggest that exercise can ______.
【正确答案】
C
【答案解析】[解析] 本题问的是卡梅伦博士的研究表明运动有什么好处。文章第一段第三句说到“...exercise can make blood vessels, including those in the brain, stronger and more fullyr developed”，由此可知，运动不仅能使血管更加强壮，发育更好，而且还能使大脑部位的血管收到同样的效果。因此C选项符合原文内容，为正确答案。原文只是说运动能使血管更强壮，发育更好，而不是生成新的血管，故A项说法错误。B和D两项在原文没有提到。
单选题
Margaret Barnes thinks that a lack of movement in infancy can ______.
【正确答案】
A
【答案解析】[解析] 本题问的是Margaret认为在婴儿期缺少运动会有什么后果。文章第二段第五句提到“She thinks that...a lack of movement as babies”，由此可知Margaret认为一些孩子在小学、中学时的学习缺陷就是因为婴儿期缺少运动引起的。A选项符合原文内容，为正确答案。文章第二段倒数第三句说到“Babies need movement that stimulates their five senses”，可知婴儿需要运动来刺激他们的五种感官，故C项说法错误。而文章第一段最后一句说到“exercise can literally cause physical changes in the brain”，可知运动可以使大脑产生生理变化。故D项说法错误。B项在原文没有提到。
单选题
The expression "beef up" in paragraph 3 means ______.
单选题
To be beneficial, exercise for older people should ______.
【正确答案】
D
【答案解析】[解析] 本题问的是老年人怎样运动才有益。文章第三段第四句提到“The exercise does not have to be very difficult, but it does have to increase the heart rate”，由此可知，对于老人来说，运动不要太难，但是得增加他们的心率。D选项符合原文内容。因此，本题的正确答案为D。本段第五句提到运动需要具有一定的复杂性(complexity)，而不是指难度，而且根据原文第四句中明确提到“The exercise does not have to be very difficult”，因此C项错误。A项和B项文中均未提及。
单选题
The title of the passage implies that ______.
【正确答案】
C
【答案解析】[解析] 本文主要介绍的是运动对于大脑发育的好处，且文章最后一段最后一句明确提到“And your brain can benefit from as little as two to three hours of exercise a week”，由此可知，文章标题暗含的意思就是运动可以使大脑更加强壮。C选项符合原文内容。因此，本题的正确答案为C。A、B项虽然都包含了“smart”一词，但是并不是文章中对于“smart”的理解，文章中的smart指的是运动对于大脑发育的好处，而不是指聪明的人或者运动本身是否聪明，因此A、B项不符合题意。文中没有涉及运动是否时尚，因此D项排除。