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训练2 体裁：说明文 主题：科普知识 难度：★★★★★ 建议用时：9 min 正确率： /4
新素材·大脑发育（原创）①Your brain(脑) only goes into “adult mode” in your 30s, according to new research. Scientists scanned the brains of about 4,000 people—from babies under the age of one to 90-year-olds.
②The researchers found four major “turning points” when brains rewire themselves: at the age of 9，32，66，and 83.
③From birth until the age of nine, children’s brains grow white and grey matter. Grey matter is a type of brain tissue that processes and interprets information related to memory and emotion. White matter carries signals between chunks of grey matter and helps with learning and paying attention. During this time, the many connections between young children’s brain cells start to reduce. The researchers call this era “childhood”.
④The second era, “adolescence”, lasts from age 9 until 32. The brain grows more white matter, improving communication(交流) inside the brain. In this era, people’s brains get better at remembering, paying attention, and solving problems.
⑤From 32 onwards, the brain enters “adulthood”. This is the longest era in a person’s life. The brain becomes more stable(稳定的) and brain regions become more separate from each other. In “early aging” (which is 66－83 years old) and “late aging” (from 83 onwards), the connections in the brain start to reduce and this quickens as the brain ages.
⑥“These eras provide important context for what our brains might be best at, or more vulnerable to, at different stages of our lives,” said Alexa Mousley, a student at Cambridge University who led the research. She added that it could help us understand why some brains develop differently, whether in childhood or old age.
1. Which of the following can be put in the blank in Paragraph 2?
A. However, not everyone experiences these turning points in the same way.
B. In fact, the brain can be divided into four main eras based on these turning points.
C. This means that human brains have five different eras during the course of people’s lives.
D. These turning points mark the beginning and end of different stages of brain development.
2. Which picture shows the relationship between ages (x) and the number of brain connections (y)?
3. What’s the structure of the passage?
A. ①/②/③④⑤/⑥
B. ①/②/③④⑤⑥
C. ①②/③④⑤⑥
D. ①②/③④/⑤⑥
4. What does the passage mainly talk about?
A. What grey matter and white matter do.
B. Why people become adults in their 30s.
C. How the brain changes at different ages.
D. How to keep the brain young and healthy.
＞＞ 文章主旨题
新素材·大脑发育（原创）①Your brain(脑) only goes into “adult mode” in your 30s, according to new research. Scientists scanned the brains of about 4,000 people—from babies under the age of one to 90-year-olds.
②The researchers found four major “turning points” when brains rewire themselves: at the age of 9，32，66，and 83.
C
These eras help us understand how the brain is wired at different stages of life. The brain’s “wiring” means the ways that the different parts of the brain connect. It controls how the brain sends and receives signals and affects how people experience the world, make decisions, and form memories.③From birth until the age of nine, children’s brains grow white and grey matter. Grey matter is a type of brain tissue that processes and interprets information related to memory and emotion. White matter carries signals between chunks of grey matter and helps with learning and paying attention. During this time, the many connections between young children’s brain cells start to reduce. The researchers call this era “childhood”.
④The second era, “adolescence”, lasts from age 9 until 32. The brain grows more white matter, improving communication(交流) inside the brain. In this era, people’s brains get better at remembering, paying attention, and solving problems.
⑤From 32 onwards, the brain enters “adulthood”. This is the longest era in a person’s life. The brain becomes more stable(稳定的) and brain regions become more separate from each other. In “early aging” (which is 66－83 years old) and “late aging” (from 83 onwards), the connections in the brain start to reduce and this quickens as the brain ages.
⑥“These eras provide important context for what our brains might be best at, or more vulnerable to, at different stages of our lives,” said Alexa Mousley, a student at Cambridge University who led the research. She added that it could help us understand why some brains develop differently, whether in childhood or old age.
1. Which of the following can be put in the blank in Paragraph 2?
A. However, not everyone experiences these turning points in the same way.
B. In fact, the brain can be divided into four main eras based on these turning points.
C. This means that human brains have five different eras during the course of people’s lives.
D. These turning points mark the beginning and end of different stages of brain development.
2. Which picture shows the relationship between ages (x) and the number of brain connections (y)?
3. What’s the structure of the passage?
A. ①/②/③④⑤/⑥
B. ①/②/③④⑤⑥
C. ①②/③④⑤⑥
D. ①②/③④/⑤⑥
4. What does the passage mainly talk about?
A. What grey matter and white matter do.
B. Why people become adults in their 30s.
C. How the brain changes at different ages.
D. How to keep the brain young and healthy.
＞＞ 文章主旨题
答案
【语篇解读】本文是一篇说明文。文章主要介绍了研究发现人类大脑一生中有四个转折点：9岁、32岁、66岁和83岁，并介绍了不同阶段的大脑发育特征。
1. C 补全文章题。上文提到研究人员发现了大脑重组的四个“转折点”，分别为9岁、32岁、66岁和83岁，下文提到这些时代帮助我们了解大脑在生命的不同阶段如何连接，此处应说明“四个转折点划分出五个时代”；C项“这意味着人类大脑在人的一生中五个不同的时代。”符合语境。故选C。
2. A 图示理解题。根据第三段“During this time, the many connections between young children's brain cells start to reduce.”可知儿童期（出生—9岁）脑细胞间的连接开始减少；根据第四段“The brain grows more white matter, improving communication inside the brain.”可知青春期（9－32岁）大脑内部交流改善，即连接优化；根据第五段“The brain becomes more stable and brain regions become more separate from each other. In 'early aging' (which is 66－83 years old) and 'late aging' (from 83 onwards), the connections in the brain start to reduce and this quickens as the brain ages.”可知成年期（32－66岁）连接稳定，衰老期（66岁以后）连接开始减少且随着大脑年龄的增长而加快；综上，儿童期下降，青春期上升，成年期基本不变，衰老期下降。故选A。
3. A 篇章结构题。结合文章内容可知，本文第一段引入研究主题；第二段介绍四个转折点与五个时代的概念；第三至五段分别介绍五个时代的特点；第六段介绍研究的意义。故选A。
4. C 文章主旨题。结合文章内容可知，本文主要介绍了人类大脑在儿童期、青春期、成年期、早衰期和晚衰期不同阶段的发育特征。故选C。
1. C 补全文章题。上文提到研究人员发现了大脑重组的四个“转折点”，分别为9岁、32岁、66岁和83岁，下文提到这些时代帮助我们了解大脑在生命的不同阶段如何连接，此处应说明“四个转折点划分出五个时代”；C项“这意味着人类大脑在人的一生中五个不同的时代。”符合语境。故选C。
2. A 图示理解题。根据第三段“During this time, the many connections between young children's brain cells start to reduce.”可知儿童期（出生—9岁）脑细胞间的连接开始减少；根据第四段“The brain grows more white matter, improving communication inside the brain.”可知青春期（9－32岁）大脑内部交流改善，即连接优化；根据第五段“The brain becomes more stable and brain regions become more separate from each other. In 'early aging' (which is 66－83 years old) and 'late aging' (from 83 onwards), the connections in the brain start to reduce and this quickens as the brain ages.”可知成年期（32－66岁）连接稳定，衰老期（66岁以后）连接开始减少且随着大脑年龄的增长而加快；综上，儿童期下降，青春期上升，成年期基本不变，衰老期下降。故选A。
3. A 篇章结构题。结合文章内容可知，本文第一段引入研究主题；第二段介绍四个转折点与五个时代的概念；第三至五段分别介绍五个时代的特点；第六段介绍研究的意义。故选A。
4. C 文章主旨题。结合文章内容可知，本文主要介绍了人类大脑在儿童期、青春期、成年期、早衰期和晚衰期不同阶段的发育特征。故选C。
解析
【分析】
1. 第1题需结合上下文逻辑，上文提及大脑重组的四个转折点，下文用“these eras”指代相关阶段，需找衔接转折点与时代的选项；
2. 第2题需梳理各年龄段脑连接的变化趋势：儿童期（出生-9岁）连接减少、青春期（9-32岁）连接优化上升、成年期（32-66岁）稳定、衰老期（66岁后）连接减少，对应图示变化；
3. 第3题需划分段落功能：①引入研究主题，②介绍转折点与时代，③-⑤分述各时代特点，⑥说明研究意义；
4. 第4题需提炼文章核心内容，排除片面选项。
【解析】
1. 第1题：上文提到四个转折点，下文用“these eras”指代阶段，C项“这意味着人类大脑在一生中五个不同的时代”衔接上下文，符合逻辑，故选C；
2. 第2题：根据原文，儿童期脑连接减少，青春期连接优化上升，成年期稳定，衰老期连接减少，对应图示A的变化，故选A；
3. 第3题：①段引入研究，②段讲转折点与时代，③-⑤段分述各时代，⑥段讲研究意义，结构为①/②/③④⑤/⑥，故选A；
4. 第4题：文章围绕大脑在不同年龄的发育变化展开，A为细节、B片面、D未提及，故选C。
【答案】
1. C 2. A 3. A 4. C
【知识点】
补全句子；图表理解；主旨大意
【点评】
本文为科普说明文，围绕大脑发育阶段展开，考察多种阅读题型，需结合上下文、原文细节及段落功能解题。
【难度系数】
0.5
1. 第1题需结合上下文逻辑，上文提及大脑重组的四个转折点，下文用“these eras”指代相关阶段，需找衔接转折点与时代的选项；
2. 第2题需梳理各年龄段脑连接的变化趋势：儿童期（出生-9岁）连接减少、青春期（9-32岁）连接优化上升、成年期（32-66岁）稳定、衰老期（66岁后）连接减少，对应图示变化；
3. 第3题需划分段落功能：①引入研究主题，②介绍转折点与时代，③-⑤分述各时代特点，⑥说明研究意义；
4. 第4题需提炼文章核心内容，排除片面选项。
【解析】
1. 第1题：上文提到四个转折点，下文用“these eras”指代阶段，C项“这意味着人类大脑在一生中五个不同的时代”衔接上下文，符合逻辑，故选C；
2. 第2题：根据原文，儿童期脑连接减少，青春期连接优化上升，成年期稳定，衰老期连接减少，对应图示A的变化，故选A；
3. 第3题：①段引入研究，②段讲转折点与时代，③-⑤段分述各时代，⑥段讲研究意义，结构为①/②/③④⑤/⑥，故选A；
4. 第4题：文章围绕大脑在不同年龄的发育变化展开，A为细节、B片面、D未提及，故选C。
【答案】
1. C 2. A 3. A 4. C
【知识点】
补全句子；图表理解；主旨大意
【点评】
本文为科普说明文，围绕大脑发育阶段展开，考察多种阅读题型，需结合上下文、原文细节及段落功能解题。
【难度系数】
0.5
