2025-2026学年译林版（2024）八年级英语上册阅读讲义-说明文

阅读专项—— 说明文 阅读一： Every dog should learn the command (命令) “no”. When the dog hears “no”, she should stop doing what she is doing before she hurts (伤害) herself, hurts you or someone else, or breaks things. Sometimes giving the command with body languages (语言) is useful. The command will help your dog learn a little self-control (自控). Here are some things that you can do. 1. Show your dog the behavior To teach the dog “no”, begin by showing her the behavior (行为) you want her to know. For example, show her a treat in your hand, and then say “no” before closing your fist (拳头) around the treat. Let her smell at your hand, but don’t give her the treat. If she stops trying and turns away, give her a treat from your other hand. 2. Have patience You can do the exercise ten times or even more before your dog understands that she gets the treat by leaving your closed hand alone. Stay patient enough with her, and always give a good treat if she can do it well. 3. ______________ Your dog will understand you by watching what you are doing. So, watch your body language. Stand tall and give the command in a strong voice, but don’t try to make her angry. You want her to understand and follow the command, not to make her afraid. 4. Teach your dog to follow the command with the treat on the floor “No” is easier when your dog can’t reach the treat anyway (when it’s in your fist). The next step is to place the treat on the floor with your hand. You may have to start with your hand completely around the treat, but over some times, begin lifting your hand until she stops when you say “no” even with the treat in the open. 参考翻译 每只狗都应该学会“不”的命令。当狗听到“不”时，她应该停止正在做的事情，以免伤害自己、你或他人，或者损坏物品。有时结合肢体语言发出命令会很有用。这个命令将帮助你的狗学会一些自我控制。以下是一些你可以做的事情。 1.展示给狗的行为 要教狗“不”，首先向她展示你希望她知道的行为。例如，把一块零食放在手掌中，然后在合上拳头之前说“不”。让她闻你的手，但不要给她零食。如果她停止尝试并转身离开，用另一只手给她一块零食。 2.要有耐心 在狗明白只有在不碰你紧握的手的情况下才会得到零食之前，你可以做这个练习十次甚至更多。对她保持足够的耐心，并且如果她做得好，总是给她一块好的零食。 3.注意你的肢体语言 你的狗会通过观察你的行为来理解你。所以，注意你的肢体语言。站直，用坚定的声音发出命令，但不要试图让她生气。你希望她理解并遵循命令，而不是让她害怕。 4.教你的狗在零食在地上时遵循命令 当狗无论如何都无法拿到零食（比如在你的拳头里）时，“不”这个命令更容易执行。下一步是用手把零食放在地上。你可能需要从完全握住零食开始，但经过几次之后，逐渐抬起你的手，直到她说“不”时即使零食在开放状态下也会停下来。 单词 command /kəˈmɑːnd/ n.(给人或动物的)命令；指令；控制 v.命令；指挥，居高临下地掌控 复数：commands第三人称单数：commands 现在进行时：commanding过去式：commanded 过去分词：commanded fist /fɪst/ n.拳头；拳 vt.紧握；握成拳；用拳打 复数：fists第三人称单数：fists现在进行时：fisting 过去式：fisted过去分词：fisted completely /kəmˈpliːtli/ adv.完全地；完整地；彻底地 记忆complete adj.齐全的 + -ly ...地 习题 1．Which of the following sentences can be put in ________? A．Talk to your dog gently B．Be careful with your body language C．Make friends with your dog D．Teach your dog to follow you all the time 2．What can we learn from the passage? A．Dogs always get hurt and can’t control themselves. B．People like playing tricks on their own pet dogs. C．It’s very easy to teach a dog to understand her owner. D．Giving dogs a treat is very important when teaching “no”. 3．What is the passage mainly about? A．Teaching pet dogs to understand “no”. B．Showing the ways to live with dogs. C．Stopping dogs hurting people around them. D．Showing the love between animals and people. 阅读二： All living things on Earth need water to live, so water is very important. In fact, the water on Earth is moving around all the time. The water cycle (循环) is a natural course that takes water from the ground and the sky and brings it back to Earth again. This course allows water to move from one part of Earth to another. It is a cycle that happens the whole year and is most active in summer at the mouth of the Yangtze River. In this article, we will explore (探索) the water cycle and discuss its importance for Earth. The water cycle always begins with water vapour (蒸汽). When it’s hot outside, you can see clouds forming in the sky. These clouds are made of water vapour that comes from the ground, plants and rivers. As water vapour rises into the sky, it cools down and becomes clouds. After that, clouds travel through the sky and fall back to Earth as rain or snow. Then, water runs through rivers and oceans and finally return s to Earth again in different forms like rainwater or snow. The water cycle plays an important part in protecting our Earth’s climate (气候). It keeps our climate healthy. On top of that, it takes water from rivers and oceans and brings it to the areas that don’t have enough water. Without the cycle, we would face many problems. When there is too much water in one place, it becomes a flood. When water is badly in need, it becomes a drought (旱灾). Besides, water vapour can take heat from the sun and keep our Earth cool. The water cycle is also an important natural course that keeps our planet alive because it’s important for plants and animals to drink water and for our rivers to stay flowing with water. Understanding the water cycle can help us enjoy the beauty of nature, know how our planet works and develop better ways to protect our Earth. And that is a duty we should take on. 参考翻译 地球上所有的生物都需要水才能生存，所以水非常重要。事实上，地球上的水一直在流动。水循环是一个自然过程，它从地面和天空取水，并将其带回地球。这个过程允许水从地球的一个部分移动到另一个部分。这是一个全年发生的循环，在长江口的夏季最为活跃。在这篇文章中，我们将探索水循环并讨论它对地球的重要性。 水循环总是从水蒸气开始的。当外面很热的时候，你可以看到天空中形成的云。这些云是由来自地面、植物和河流的水蒸气组成的。当水蒸气上升到天空中时，它会冷却并变成云。之后，云层穿过天空，以雨或雪的形式落回地球。然后，水流过河流和海洋，最终以雨水或雪等不同形式再次返回地球。 水循环在保护地球气候方面起着重要作用。它使我们的气候保持健康。最重要的是，它从河流和海洋中取水，并将其带到没有足够水的地区。如果没有循环，我们将面临许多问题。当一个地方的水太多时，就会变成洪水。当急需水时，就会变成干旱。此外，水蒸气可以从太阳吸收热量，使我们的地球保持凉爽。 水循环也是一个重要的自然过程，它使我们的星球保持活力，因为植物和动物喝水以及我们的河流保持水流是很重要的。了解水循环可以帮助我们享受大自然的美丽，了解我们的星球是如何运作的，并开发更好的方法来保护我们的地球。这是我们应该承担的责任。 单词 discuss /dɪˈskʌs/ vt.讨论；论述；谈论；商量；详述 第三人称单数：discusses现在进行时：discussing 过去式：discussed过去分词：discussed protect /prəˈtekt/ v.防护；实行贸易保护 第三人称单数：protects现在进行时：protecting 过去式：protected过去分词：protected climate /ˈklaɪmət/ n.气候；气候区；风气；倾向；思潮；环境气氛 复数：climates drought /draʊt/ n.干旱；旱灾；久旱 复数：droughts 习题 1．The water cycle might be most active in ________ at the mouth of the Yangtze River A．January B．April C．July D．December 2．Which facts of the following are, true according to the passage? ① Water vapour can keep our Earth warm. ②Water returns to Earth in only one form. ③Water vapour becomes clouds when it cools down. ④ There may be some disasters without water vapour. A．③④ B．②③ C．①② D．①④ 3．What’s the structure of this passage? (①=Paragraph 1,②=Paragraph 2…) A． B． C． D． 4．In the last paragraph, the writer wants us to ________. A．save water B．protect our Earth C．get close to nature D．protect plants and animals 阅读练习 练习一 Many people have such a feeling in their life. They have too many things to do every day, but they don’t have enough time. Well, “not having enough time” is a feeling for many people. Every person only has 24 hours a day, but some people put too many things in the “time box”. How can you put all of the things into your small “time box”? You can do that by making what you have to do easy. Make a list of all the things you do every day. What games do you play on your phone or the computer? How much time do you spend on We Chat or QQ? How long do you watch TV or movies? Then maybe you will find you put a lot of useless things into your box. What can you do? Take some out and ask yourself: What am I going to do if I can only do one thing today? Then just do the most important thing first. It will be helpful to you. 1．What do many people feel in their life? A．They don’t know what is important. B．They’re too busy to do what they like. C．There are lots of boring things to do. D．They have little time but too many things to do. 2．What does the underlined word “list” mean in Chinese? A．答案 B．列表 C．笔记 D．选择 3．Why does the writer ask two questions in paragraph 4? A．To tell us what things we must do every day. B．To help us know how to work and study well. C．To tell us to do the most important things first. D．To help us know what things we can’t do every day. 4．In which part of a magazine can we most probably read the text? A．Sports B．Problems C．Stories D．Games 练习二 ①They may look like something out of an amazing movie, but narwhals (独角鲸) are very real animals. Here are some fun facts about narwhals. ②Narwhals change color a few times during their lives. When they’re born, most baby narwhals are blue-gray. But as they grow older, their color changes to blue-black, while adult narwhals are usually gray with dark spots. Old narwhals are almost all white. ③Like elephant tusks (长牙), a narwhal’s tusk is a tooth. It can grow as long as 3 meters.    ▲   . They use tusks to attract female narwhals. Narwhals also use their tusks to hit fish so they can catch and eat fish easily. And some narwhals even have two tusks! ④Narwhals are among the deepest diving (潜水) whales, reaching depths of about 1,500 meters—although some can reach depths of over 1,700 meters, according to the University of Washington. Narwhals usually stay less than 50 meters from the water, however. But they can stay underwater for 25 minutes before needing to come up for air! ⑤Living in the cold Arctic waters of Greenland, Norway, Russia and Canada, narwhals don’t have a dorsal fin (背鳍). The absence (缺乏) of a dorsal fin makes the narwhal prevent heat loss and helps them to swim under the ice. ⑥Known as the “unicorns of the sea”, narwhals are really interesting animals you must watch when you take a trip to the Arctic Circle. 1．What color is a young narwhal? A．Blue-gray. B．Blue-black. C．Almost all white. D．Gray with darker spots. 2．Which sentence is the best for “   ▲   ” in Paragraph 3? A．It comes out of its head. B．Most female narwhals do not have tusks. C．Male (雄性) narwhals all have tusks. D．Scientists are still unsure about uses of their tusks. 3．A narwhal can dive into the water up to over ________ according to the University of Washington. A．1,500 meters B．1,700 meters C．50 meters D．25 meters 4．Which is the best subtitle (小标题) for Paragraph 5? A．Deep divers B．One big tooth C．Changing colors D．Absence of a dorsal fin 5．Which is the best structure of the passage?(P=Paragraph) A． B． C． D． 练习三 Do you find that you learn things faster than your parents? You could be right! Scientists in the USA have found that school-aged children learn new things and skills faster than grown-ups. This has something to do with a chemical (化学物质) called GABA in our brains (大脑). It makes brain noise less so that we can learn things more easily. It also makes new information stay longer in our heads. The scientists studied the brains of children (8—11 years old) and adults (18—35 years old) before, during and after doing a learning task. The finding shows that when children learn new things, the amount (数量) of GABA increases (增加) quickly. But there’s little change in adults’ brains. This tells us why children are better learners than adults. The scientists said the finding is useful. It tells teachers and parents to let children learn anything in their childhood, from riding a bike to playing an instrument (乐器). It could also help adults learn faster by increasing the amount of GABA in their brains. 1．Why do children learn faster than adults? A．Because children’s brains have more GABA than adults’. B．Because teachers and parents help children learn faster. C．Because GABA in children’s brains increases while learning. D．Because there’s no change in adults’brains when they learn. 2．Which of the following about GABA is right? A．It helps children learn things in their childhood. B．It makes information stay shorter in adults’ brains. C．It makes brain noise to make learning more easily. D．It is useless to help adults learn new things and skills. 3．What is the article mainly about? A．Why children learn faster than adults. B．What scientists are studying. C．How scientists help children learn. D．What the chemical GABA is. 4．What can we learn from the passage? A．Practice makes perfect. B．Start learning as early as you can. C．You are never too old to learn. D．Great hopes make a great man. 阅读一： 【答案】1．B 2．D 3．A 【导语】本文主要介绍教宠物狗懂得“No”。 1．推理判断题。根据“Your dog will understand you by watching what you are doing. So, watch your body language.”可知，你的狗会通过观察你在做什么来理解你。所以，注意你的肢体语言。选项B“注意你的肢体语言”符合语境，故选B。 2．细节理解题。根据“If she stops trying and turns away, give her a treat from your other hand.”可知，如果她不再尝试，转过身去，用你的另一只手给她一些奖励。故选D。 3．主旨大意题。本文主要介绍教宠物狗懂得“No”，故选A。 阅读二： 答案解析 【答案】1．C 2．A 3．C 4．B 【导语】本文主要讲述了水循环的定义，水循环在保护地球气候和使我们的星球保持活力方面起着重要作用。 1．细节理解题。根据第一段“It is a cycle that happens the whole year and is most active in summer at the mouth of the Yangtze River”可知，这是一个全年都会发生的循环，并且在长江口的夏天最活跃。结合选项可知，July“七月”属于夏天，符合题意。故选C。 2．细节理解题。根据第二段“As water vapour rises into the sky, it cools down and becomes clouds.”可知，当水蒸气上升到天空中时，它会冷却并变成云。也就是说，水蒸气冷却后变成云。根据第三段“When there is too much water in one place, it becomes a flood. When water is badly in need, it becomes a drought (旱灾).”可知，当一个地方的水太多时，就会变成洪水。当急需水的时候，就会变成干旱。也就是说，如果没有水蒸气，可能会发生一些灾难。A选项里的两点描述正确。故选A。 3．篇章结构题。根据第一段“In this article, we will explore (探索) the water cycle and discuss its importance for Earth.”可知，第1段主要介绍水循环的定义，并要探讨它对地球的重要性。根据第二段“The water cycle always begins with water vapour (蒸汽)…Then, water runs through rivers and oceans and finally return s to Earth again in different forms like rainwater or snow.”可知，第2段主要讲述水变成雨雪的循环过程。根据第三段“The water cycle plays an important part in protecting our Earth’s climate (气候).”可知，第3段主要讲述水循环在保护地球的气候方面的作用。根据第四段“The water cycle is also an important natural course that keeps our planet alive…And that is a duty we should take on.”可知，第4段主要讲述水循环使我们的星球保持活力，我们应当保护地球。可见，第1段是总述水循环。2-4段详细介绍水循环的过程一起水循环对地球的重要性。所以选项C的篇章结构是对的。故选C。 4．推理判断题。根据“Understanding the water cycle can help us enjoy the beauty of nature, know how our planet works and develop better ways to protect our Earth. And that is a duty we should take on.”可知，了解水循环可以帮助我们欣赏大自然的美丽。了解我们的星球是如何运作的，并制定更好的方法来保护我们的地球。这是我们应该承担的责任。可见，在最后一段里，作者是想让我们保护地球。故选B。 练习一： 【答案】1．D 2．B 3．C 4．B 【导语】本文是一篇说明文。文章介绍了如何合理安排繁琐的事情。 1．细节理解题。根据“They have too many things to do every day, but they don’t have enough time”可知， 人们每天要做的事情很多，但是时间很少。故选D。 2．词句猜测题。根据“Make a list of all the things you do every day.”和后面的问句可推测出，应是对每天要做的事情里一个清单，所以划线单词list表示“列表”。故选B。 3．推理判断题。根据“Take some out and ask yourself: What am I going to do if I can only do one thing today? Then just do the most important thing first. It will be helpful to you.”可知，问题的目的是告诉自己先做最重要的事情。故选C。 4．推理判断题。根据“Many people have such a feeling in their life. They have too many things to do every day, but they don’t have enough time.”可知，本篇主要在解决事情多，时间少的问题，所以可能在杂志的“问题”部分看到。故选B。 练习二： 【答案】1．B 2．C 3．B 4．D 5．D 【导语】本文主要介绍了一些独角鲸的事实。 1．细节理解题。根据“But as they grow older, their color changes to blue-black”可知，年轻的独角鲸是蓝黑色，故选B。 2．推理判断题。根据“They use tusks to attract female narwhals”可知，这里说他们用长牙吸引雌性独角鲸，所以这个they指的是雄性独角鲸，选项C“雄性独角鲸都有长牙。”符合，故选C。 3．细节理解题。根据“although some can reach depths of over 1,700 meters”可知，独角鲸可以潜入水下1700多米。故选B。 4．最佳标题题。根据“Living in the cold Arctic waters of Greenland, Norway, Russia and Canada, narwhals don’t have a dorsal fin (背鳍). The absence (缺乏) of a dorsal fin makes the narwhal prevent heat loss and helps them to swim under the ice.”可知，生活在格陵兰岛、挪威、俄罗斯和加拿大寒冷的北极水域的独角鲸没有背鳍。背鳍的缺失使独角鲸防止热量流失，并帮助它们在冰下游泳。所以选项D“没有背鳍”符合，故选D。 5．篇章结构题。文章第一段引出独角鲸的主题；第二段到第五段介绍了一些独角鲸的事实；最后一段建议当你去北极圈旅行时，可以去看看它们。D选项结构符合，故选D。 练习三： 【答案】1．C 2．A 3．A 4．B 【导语】本文主要讲述美国的科学家发现，学龄儿童学习知识和技能等新事物的速度比成年人快，这是因为我们大脑中的GABA。 1．细节理解题。根据第三段提到“The finding shows that when children learn new things, the amount (数量) of GABA increases (增加) quickly. But there’s little change in adults’ brains. This tells us why children are better learners than adults.”可知，因为儿童大脑中的GABA在学习时会增加，故选C。 2．细节理解题。根据最后一段提到“The scientists said the finding is useful. It tells teachers and parents to let children learn anything in their childhood, from riding a bike to playing an instrument (乐器). ”可知，它能帮助在孩童时期学习东西，故选A。 3．主旨大意题。根据第一段提到“Do you find that you learn things faster than your parents?”可知，本文讲述了儿童学习知识和技能等新事物的速度比成年人快的原因，故选A。 4．推理判断题。根据最后一段提到“It tells teachers and parents to let children learn anything in their childhood, from riding a bike to playing an instrument (乐器). ”可知，建议孩子们尽早学习一些东西，故选B。 1 学科网（北京）股份有限公司 $$ 阅读专项 —— 说明文 阅读一： Every dog should learn the command (命令) “no”. When the dog hears “no”, she should stop doing what she is doing before she hurts (伤害) herself, hurts you or someone else, or breaks things. Sometimes giving the command with body languages (语言) is useful. The command will help your dog learn a little self-control (自控). Here are some things that you can do. 1. Show your dog the behavior To teach the dog “no”, begin by showing her the behavior (行为) you want her to know. For example, show her a treat in your hand, and then say “no” before closing your fist (拳头) around the treat. Let her smell at your hand, but don’t give her the treat. If she stops trying and turns away, give her a treat from your other hand. 2. Have patience You can do the exercise ten times or even more before your dog understands that she gets the treat by leaving your closed hand alone. Stay patient enough with her, and always give a good treat if she can do it well. 3. ______________ Your dog will understand you by watching what you are doing. So, watch your body language. Stand tall and give the command in a strong voice, but don’t try to make her angry. You want her to understand and follow the command, not to make her afraid. 4. Teach your dog to follow the command with the treat on the floor “No” is easier when your dog can’t reach the treat anyway (when it’s in your fist). The next step is to place the treat on the floor with your hand. You may have to start with your hand completely around the treat, but over some times, begin lifting your hand until she stops when you say “no” even with the treat in the open. 单词 command /kəˈmɑːnd/ n.(给人或动物的)命令；指令；控制 v.命令；指挥，居高临下地掌控 复数：commands第三人称单数：commands 现在进行时：commanding过去式：commanded 过去分词：commanded fist /fɪst/ n.拳头；拳 vt.紧握；握成拳；用拳打 复数：fists第三人称单数：fists现在进行时：fisting 过去式：fisted过去分词：fisted completely /kəmˈpliːtli/ adv.完全地；完整地；彻底地 记忆complete adj.齐全的 + -ly ...地 习题 1．Which of the following sentences can be put in ________? A．Talk to your dog gently B．Be careful with your body language C．Make friends with your dog D．Teach your dog to follow you all the time 2．What can we learn from the passage? A．Dogs always get hurt and can’t control themselves. B．People like playing tricks on their own pet dogs. C．It’s very easy to teach a dog to understand her owner. D．Giving dogs a treat is very important when teaching “no”. 3．What is the passage mainly about? A．Teaching pet dogs to understand “no”. B．Showing the ways to live with dogs. C．Stopping dogs hurting people around them. D．Showing the love between animals and people. 阅读二： All living things on Earth need water to live, so water is very important. In fact, the water on Earth is moving around all the time. The water cycle (循环) is a natural course that takes water from the ground and the sky and brings it back to Earth again. This course allows water to move from one part of Earth to another. It is a cycle that happens the whole year and is most active in summer at the mouth of the Yangtze River. In this article, we will explore (探索) the water cycle and discuss its importance for Earth. The water cycle always begins with water vapour (蒸汽). When it’s hot outside, you can see clouds forming in the sky. These clouds are made of water vapour that comes from the ground, plants and rivers. As water vapour rises into the sky, it cools down and becomes clouds. After that, clouds travel through the sky and fall back to Earth as rain or snow. Then, water runs through rivers and oceans and finally return s to Earth again in different forms like rainwater or snow. The water cycle plays an important part in protecting our Earth’s climate (气候). It keeps our climate healthy. On top of that, it takes water from rivers and oceans and brings it to the areas that don’t have enough water. Without the cycle, we would face many problems. When there is too much water in one place, it becomes a flood. When water is badly in need, it becomes a drought (旱灾). Besides, water vapour can take heat from the sun and keep our Earth cool. The water cycle is also an important natural course that keeps our planet alive because it’s important for plants and animals to drink water and for our rivers to stay flowing with water. Understanding the water cycle can help us enjoy the beauty of nature, know how our planet works and develop better ways to protect our Earth. And that is a duty we should take on. 单词 discuss /dɪˈskʌs/ vt.讨论；论述；谈论；商量；详述 第三人称单数：discusses现在进行时：discussing 过去式：discussed过去分词：discussed protect /prəˈtekt/ v.防护；实行贸易保护 第三人称单数：protects现在进行时：protecting 过去式：protected过去分词：protected climate /ˈklaɪmət/ n.气候；气候区；风气；倾向；思潮；环境气氛 复数：climates drought /draʊt/ n.干旱；旱灾；久旱 复数：droughts 习题 1．The water cycle might be most active in ________ at the mouth of the Yangtze River A．January B．April C．July D．December 2．Which facts of the following are, true according to the passage? ① Water vapour can keep our Earth warm. ②Water returns to Earth in only one form. ③Water vapour becomes clouds when it cools down. ④ There may be some disasters without water vapour. A．③④ B．②③ C．①② D．①④ 3．What’s the structure of this passage? (①=Paragraph 1,②=Paragraph 2…) A． B． C． D． 4．In the last paragraph, the writer wants us to ________. A．save water B．protect our Earth C．get close to nature D．protect plants and animals 阅读练习 练习一 Many people have such a feeling in their life. They have too many things to do every day, but they don’t have enough time. Well, “not having enough time” is a feeling for many people. Every person only has 24 hours a day, but some people put too many things in the “time box”. How can you put all of the things into your small “time box”? You can do that by making what you have to do easy. Make a list of all the things you do every day. What games do you play on your phone or the computer? How much time do you spend on We Chat or QQ? How long do you watch TV or movies? Then maybe you will find you put a lot of useless things into your box. What can you do? Take some out and ask yourself: What am I going to do if I can only do one thing today? Then just do the most important thing first. It will be helpful to you. 1．What do many people feel in their life? A．They don’t know what is important. B．They’re too busy to do what they like. C．There are lots of boring things to do. D．They have little time but too many things to do. 2．What does the underlined word “list” mean in Chinese? A．答案 B．列表 C．笔记 D．选择 3．Why does the writer ask two questions in paragraph 4? A．To tell us what things we must do every day. B．To help us know how to work and study well. C．To tell us to do the most important things first. D．To help us know what things we can’t do every day. 4．In which part of a magazine can we most probably read the text? A．Sports B．Problems C．Stories D．Games 练习二 ①They may look like something out of an amazing movie, but narwhals (独角鲸) are very real animals. Here are some fun facts about narwhals. ②Narwhals change color a few times during their lives. When they’re born, most baby narwhals are blue-gray. But as they grow older, their color changes to blue-black, while adult narwhals are usually gray with dark spots. Old narwhals are almost all white. ③Like elephant tusks (长牙), a narwhal’s tusk is a tooth. It can grow as long as 3 meters.    ▲   . They use tusks to attract female narwhals. Narwhals also use their tusks to hit fish so they can catch and eat fish easily. And some narwhals even have two tusks! ④Narwhals are among the deepest diving (潜水) whales, reaching depths of about 1,500 meters—although some can reach depths of over 1,700 meters, according to the University of Washington. Narwhals usually stay less than 50 meters from the water, however. But they can stay underwater for 25 minutes before needing to come up for air! ⑤Living in the cold Arctic waters of Greenland, Norway, Russia and Canada, narwhals don’t have a dorsal fin (背鳍). The absence (缺乏) of a dorsal fin makes the narwhal prevent heat loss and helps them to swim under the ice. ⑥Known as the “unicorns of the sea”, narwhals are really interesting animals you must watch when you take a trip to the Arctic Circle. 1．What color is a young narwhal? A．Blue-gray. B．Blue-black. C．Almost all white. D．Gray with darker spots. 2．Which sentence is the best for “   ▲   ” in Paragraph 3? A．It comes out of its head. B．Most female narwhals do not have tusks. C．Male (雄性) narwhals all have tusks. D．Scientists are still unsure about uses of their tusks. 3．A narwhal can dive into the water up to over ________ according to the University of Washington. A．1,500 meters B．1,700 meters C．50 meters D．25 meters 4．Which is the best subtitle (小标题) for Paragraph 5? A．Deep divers B．One big tooth C．Changing colors D．Absence of a dorsal fin 5．Which is the best structure of the passage?(P=Paragraph) A． B． C． D． 练习三 Do you find that you learn things faster than your parents? You could be right! Scientists in the USA have found that school-aged children learn new things and skills faster than grown-ups. This has something to do with a chemical (化学物质) called GABA in our brains (大脑). It makes brain noise less so that we can learn things more easily. It also makes new information stay longer in our heads. The scientists studied the brains of children (8—11 years old) and adults (18—35 years old) before, during and after doing a learning task. The finding shows that when children learn new things, the amount (数量) of GABA increases (增加) quickly. But there’s little change in adults’ brains. This tells us why children are better learners than adults. The scientists said the finding is useful. It tells teachers and parents to let children learn anything in their childhood, from riding a bike to playing an instrument (乐器). It could also help adults learn faster by increasing the amount of GABA in their brains. 1．Why do children learn faster than adults? A．Because children’s brains have more GABA than adults’. B．Because teachers and parents help children learn faster. C．Because GABA in children’s brains increases while learning. D．Because there’s no change in adults’brains when they learn. 2．Which of the following about GABA is right? A．It helps children learn things in their childhood. B．It makes information stay shorter in adults’ brains. C．It makes brain noise to make learning more easily. D．It is useless to help adults learn new things and skills. 3．What is the article mainly about? A．Why children learn faster than adults. B．What scientists are studying. C．How scientists help children learn. D．What the chemical GABA is. 4．What can we learn from the passage? A．Practice makes perfect. B．Start learning as early as you can. C．You are never too old to learn. D．Great hopes make a great man. 1 学科网（北京）股份有限公司 $$