问题补充：
Many people think of the brain as a mystery. They don know much about intelligence and how it works. When they do think about what intelligence is, many people believe that a person is born smart, average, or dumb — and stays that way in the whole life. But new research shows that the brain is more like a muscle — it changes and gets stronger when you use it. And scientists have been able to show just how the brain grows and gets stronger when you learn.
Everyone knows that when you lift weights, your muscles get bigger and you get stronger. A person who can lift 20 pounds when he/she starts exercising can get strong enough to lift 100 pounds after working out for a long time. Thats because the muscles become larger and stronger with exercise. And when you stop exercising, the muscles shrink and you get weaker. Thats why people say “Use it or lose it！”
But most people don know that when they practice and learn new things, parts of their brain change and get larger a lot like muscles do when they exercise. Inside the cortex (皮层) of the brain are billions of tiny nerve cells, called neurons. The nerve cells have branches connecting them to other cells in a complicated network. Communication between these brain cells is what allows us to think and solve problems. When you learn new things, these tiny connections in the brain actually multiply and get stronger. The more you challenge your mind to learn, the more your brain cells grow. Then, things that you once found very hard or even impossible to do — like speaking a foreign language or doing algebra (代数) — seem to become easy after learning them for a period of time. The result is a stronger, smarter brain.
Scientists started thinking that the human brain could develop and change when they studied animals brains. They found out that animals that lived in a challenging environment were more “perspicacious” — they were better at solving problems and learning new things.
【小题1】According to the first paragraph，.A．the function of our brain is like that of the muscleB．until now its impossible to explain the brains mysteryC．many people believe ones intelligence is naturally determinedD．ones brain grows stronger as the age increases【小题2】Training muscles is compared to .A．using the brainB．connecting things in your brainC．lifting weightsD．doing research about the brain【小题3】What is Paragraph 3 mainly about?
The complex structure of the brain.
B. How changes in the muscles affect the brain.
C. The importance of the brain.
D. How the brain becomes stronger by learning new things.
【小题4】What does the underlined word “perspicacious” in the last paragraph probably mean?A．Strong.B．Smart.C．Popular.D．Active.【小题5】The paragraph that follows the passage will most probably talk about .A．the differences between animals’ brains and humans’ brainsB．the relation between human brains and musclesC．scientists’ findings about animals’ brainsD．how to make your brain smarter through self-developmentC
答案：
(答案→)C
解析：通常情况下，很多人都认为人的智力是与生俱来的，是由先天的遗传条件决定的。但是，科学研究发现，人类大脑也可以像肌肉一样，通过学习得到发展。
【小题1】根据第一段“When they do think about what intelligence is, many people believe that a person is born smart, average, or dumb”可知，许多人认为，一个人的智力是与生俱来的，有的人天生聪明，有的智力一般，有的天生智力低下，故选C。
【小题2】根据第一段“But new research shows that the brain is more like a muscle — it changes and gets stronger when you use it.”可知，大脑就像肌肉一样，会随着不断的使用而变得更加强大，故选A。
【小题3】根据“When you learn new things, these tiny connections in the brain actually multiply and get stronger. The more you challenge your mind to learn, the more your brain cells grow.”可知，第三段主要讲的是如何通过学习使大脑变强大，故选D。
【小题4】根据“they were better at solving problems and learning new things”可知，生活在挑战性环境下的动物，它们更善于解决问题和学习新事物，科学家认为，人类大脑也可以发展并发生变化。根据破折号后面的解释可以推断，生活在挑战性环境下的动物更聪明，故选B。
【小题5】根据最后一段“Scientists started thinking that the human brain could develop and change when they studied animals brains.”可知，科学家认为人类大脑与动物大脑一样，也可以得到锻炼并变得更加聪明，最后一段介绍了动物变聪明的条件--生活在挑战性环境中，下一段有可能介绍人类如何让大脑变得更聪明，故选D。
