Unit 5 Looking into nature课件 2025-2026学年外研版八年级英语下册

Unit 5 Looking into nature Developing ideas Learning Objectives In this lesson, you will: 1.understand the listening material and grasp the key information. 2.learn that some words have different stress positions when used as different parts of speech. 3.talk about what you have learnt about the secrets of nature. Look and Say What secrets do the four pictures show? Which of the secrets interests you most? DID YOU KNOW? Nature is full of secrets. They are waiting to be explained. These include black holes, the beginning of the universe, the Loch Ness Monster and Bigfoot. These secrets awaken our curiosity and drive scientists to better understand the wonders around us. a A disappearing river in South America b The life of the people in the Amazon Rainforest c A boiling river in the Amazon Rainforest Listen to the talk and choose the correct topic. Listen again and complete the profile. What is it? It’s a boiling river as hot as 1_______________℃. What do the local people do with it? They 2_________ with it. They clean with it. They make 3_________ with it. They sometimes go swimming in it, but only after 4_______. What's the speaker's opinion? It's one of the most 5___________of the rainforest. 86 cook tea heavy rain amazing wonders Listening for opinions Expressions such as I think, I believe and I guess show people's opinions. Remember: people are sharing their ideas, so you don't have to agree. But you should listen to the other person's opinions and be polite. Learning to learn Listen to the conversation and complete the table. sunshine heat the river becomes hot 700 kilometres in the water produce possible research Listen again.Then talk about how the speakers discuss possibilities. Talking about possibilities Could, may and might are used to talk about possibilities. Words such as maybe and perhaps are used, too. We can also use the structure It's certain / (un)likely / possible that... Learning to learn Work in pairs. Choose one unsolved secret of nature and talk about possible explanations. Atlantis (亚特兰蒂斯) Crop Circle (麦田怪圈) The truth may be... It is likely that... Perhaps it's because... It's probably a result of... Useful expressions There is a (strong) possibility that... It's possible that... There's a chance that... Have you heard of...? Yes, it's very strange. I'm curious about the possible reasons. Perhaps it's because... Talk about what you have learnt about the secrets of nature in this section. Phonetics in use Stress in words (1) A word can be stressed on different syllables. If we stress the second syllable, the word is usually a verb. For example, present describes the time, while present describes an action. Listen and mark the stress. record a world record / record the temperature research scientific research / research the nature perfect a perfect gift / perfect her skills desert the biggest desert on earth / a deserted house null 48299.883 null 63946.418 $ Unit 5 Looking into nature Grammar Learning Objectives In this lesson, you will: 1. master the usage of the objective clauses with that, if or whether. 2. use object clauses correctly when writing a short passage about nature exploration. (a) For hundreds of years, people believed that dinosaurs looked like big lizards. (b) They can tell us whether dinosaurs had feathers, but that's not all. Read the sentences from the reading passage and summarise the grammar rules. that 引导的宾语从句 whether 引导的宾语从句 Now find more sentences with these structures in the reading passage. However, thanks to a piece of amber, scientists now know that this idea is wrong. They also help us understand that life on earth has always changed. In the future, amber may also help us discover if other species have changed over time. Research shows that they are a completely new species. Who knows whether this piece of amber will tell us more secrets? Grammar Rules 在复合句中作宾语的从句叫宾语从句, 它通常位于主句谓语动词（及物动词）或介词之后。基本形式为：主句的主语+主句的谓语+引导词+宾语从句。 e.g. I believe that we can achieve the goal. e.g. Can you tell me how I can get to the nearest subway station? e.g. I wonder if/whether Grace has finished her homwork. 1. that引导的宾语从句 当谓语动词表示肯定的概念，如“希望”“相信”“知道"或“说”时，其后面的句子一般用that引导。that没有任何词汇意义，只具有语法功能，目的是使读者清楚后面的句子是作前面动词的宾语的，多数情况下that可以省略。例如： I hope (that) it will snow this winter.我希望今年冬天会下雪。 I believe (that) we shall become good friends.我相信我们会成为好朋友。 Betty thinks (that) trees can improve the air. Betty认为树木可以改善空气质量。 常接that引导的宾语从句的谓语动词有:believe, expect, explain, feel, hear, hope, imagine, prefer, promise, report, say, see, tell, think, understand, warn, wish等。 that引导的宾语从句中，当主句的主语是第一人称（I / we）, 并且谓语动词是think, guess, believe, suppose, expect 等时, 如果宾语从句要表达否定意思, 一般将否定转移到主句上来, 即“否定前移”。 e.g. I don’t think the girl can do the work alone. 我认为这个女孩不能独自做这项工作。 We don’t believe that you are right. 我们相信你是错的。 2. whether/if 引导的宾语从句 当宾语从句的语义相当于一个一般疑问句时, 常用if / whether 引导, 表示 “是否” 。if / whether在句中不充当句子成分, 但不 能省略。宾语从句要用陈述句语序。 e.g. I wonder if / whether you want to attend the meeting. She didn’t say if her aunt was still with them. I don’t know whether you like flowers. 以下情况只能用whether： 与or not 连用时，只能用whether。 e.g. I’m wondering whether I should go to the party or not. 在介词后只能用whether。 e.g. They are talking about whether the boy can win the game again. 与动词不定式连用时，只能用whether。 e.g. I can’t decide whether to buy the shoes. 1 Is there life in outer space? Scientist aren’t sure. _______________________________________________________ 2 "I want to be a scientist and study plants," John told his parents. ________________________________________________________ 3 Is Mr Brown interested in insects or birds? Emily wants to know. ________________________________________________________ Grammar Exercises Connect the sentences with that, if or whether. Scientist aren’t sure if/whether there is life in outer space. John told his parents that he wanted to be a scientist and study plants. Emily wants to know whether Mr Brown is interested in insects or birds. Complete the messages with that, if or whether. MESSAGE BOARD Hello, I went to your museum today. You missed Pluto in the model of the solar system. There were only eight planets in it. I don't know ¹___________this is a mistake. if/whether Dear Daniel, In the past, people thought 2__________there were nine planets. However, questions were raised about 3_________ Pluto was a planet. In 2006, scientists agreed 4__________ that whether that a true planet: 1. moves around the sun 2.is round (or nearly round) 3. can clear things in its way Pluto doesn't meet the third point. Therefore, we now believe 5_________ there are eight true planets in the solar system. That's why Pluto isn't part of the model. Please let me know 6_________ you need more information. that if/whether Work in pairs. Look at the notice and write a short passage about exploring nature. Use the words and expressions from the reading passage and the Useful expressions to help you. Useful expressions For hundreds of years, people believed that... ... made an amazing discovery. By..., ... found / realised / saw that... It proves that... It teaches us that... Research shows that... ................................................................... $Welcome to the amazon rainforest. Now i'd like to present a special river to you. Since ancient times, people have talked about a boiling river in the rainforest. Many people love at this story, but in fact it's true. The water can be as hot as eighty six degrees salus people here cook with IT, clean with IT and make tea with IT. There's no need to make a fire. The water only cools down after heavy rain. Then people go swimming in IT. I think it's one of the most amazing wonders of the rain forest. Secrets count in time. Imagine a dinosaur in an ancient forest. IT is running around looking for its next meal with an angry cry. IT opens its mouth, raises its beautiful feather covered arms and wait favs on a dinosaur. For hundreds of years, people believed that dinosaurs ks like huge lizard. Just look at all those dinosaurs in books, films and T. V. shows. However, thanks to a piece of member, scientists now know that this idea is wrong. In the Amber from southeast dasia, they found the tale of a dinosaur with feathers, these beautiful golden stones quietly keep pieces of the past. They can tell us whether dinosaur s had feathers, but that's not all. They also help us understand that life honor has always changed. A piece of Amber from northern europe, for example, holds a flower. This species no longer grows in this area, but the find prove that I did thirty five million years ago. In the future, Amber may also help us discover if other species have changed over time. thanks. November, more than three hundred unknown species have been discovered in a piece of Amber from africa. Scientists found thirteen ends. Research shows that they are a completely new species. Scientists used to believe that ants came from the northern half of the earth. The discovery of this african species has changed old beliefs about the history of ants. Who knows whether this piece of amer will tell us more secrets as a window? On the past, Amber has been much studied, however, is still not fully understood. We should put more effort into research, then we can use this key to unlock more secrets of nature. Unit 5 Looking into nature Presenting ideas & Reflection Learning Objectives In this lesson, you will: 1.make a poster about an achievement in nature exploration. 2.present your poster in class. Task In this class, you are going to: Make a poster about an achievement in nature exploration. Step 1 Work in groups. Search for information about achievements in nature exploration.Then take a group vote to decide on the achievement for your poster. Why is it important? What spirit was needed to achieve it? What is it? Who made it? Step 2 Organise your ideas with the help of the following outline and make your poster.You may use the following language tips or find useful expressions or sentences from this unit. Title of the poster What is it? — It's an important achievement in space / land / sea / ... exploration.. Who made it? — The achievement was first made by... — The person who made the achievement is... Why is it important? —It helps us understand... —It can tell us... —It proves that... —Thanks to..., we now know... —It means that we can... —It helps to explain... —This achievement has changed... What spirit is needed to realise it? — ... worked hard to explore... — ... never stopped trying new ways / methods... — With..., he / she carried on with the research. — To make an achievement, we should be ready to face challenges. Step 3 Practise and present your poster to the class. Step 4 Vote on the best three posters and the best three presentations. Reflection 1. After completing this unit, I understand more about nature exploration. 2. To express my understanding, I can ... use words and expressions in the unit to talk about nature exploration. use object clauses with that, if and whether to describe discoveries in nature exploration describe the spirit of nature exploration. * 1=excellent 2=good 3=not yet 3. I still need to improve: _____________________________ _________________________________________________ $ Unit 5 Looking into nature Reading Learning Objectives In this lesson, you will: 1. get the main idea and key details from the passage. 2. analyze Wang’s spirits and talk about what you can learn from him. Look and Say What do the pictures show? Who do you think drew them? The pictures show some scientific drawings about plants. Someone who loves plants and wants to explore more about them. Look at the photos on the right and read the words below them. Then answer the questions. Use the words and expressions to help you. study love of nature carry on with lifelong exploration plants discover 1 What do you think the person's job might be? 2 How would you describe the person? 1. I think his job is studying plants—recording their detailed features to help discover and identify plant species. 2. He must be someone with a deep love of nature and a passion for plants. He’d also be dedicated to a lifelong exploration of plant science. Read the passage and check your answers. 1 Nature presents us with endless wonders. Most people get interested and ask questions. But one person took his interest all the way to the fields. He was born in the flowering season of early summer, and made plants his life. This person was Wang Wencai. 2 For over 70 years, Professor Wang explored China's plants with great passion and hard work. He discovered and named about 1,370 new plant species. To carry out his research, he spent years in wild mountains and forests. Once, he fell seriously ill while doing field work in Yunnan. Though he nearly died, Wang never stopped his work. He lost sight in his right eye at the age of 83. But he didn't let anybody know. With a magnifier in hand, he still carried on with his research for another 10 years. 3 Despite his huge success, Wang seldom thought about personal honour or wealth. Although he received the First Class Award of National Natural Science Award twice, he hardly mentioned it. For him, the award belonged to the team, and he was just doing his job. In fact,Wang was always quiet about his achievements. He was such a great scientist. But for a long time, even his granddaughter had no idea. 4 Plants grow and sleep with the seasons. So did Professor Wang. He passed away at the age of 96 with the falling leaves of autumn. When people came to say goodbye, they didn't hear any sad notes. Instead, they got to listen to Beethoven's Pastoral Symphony. This was Wang's favourite piece of music. It softly told people about his lifelong exploration and love of nature. Complete the diagram with the words and expressions from the passage. Plants for life Wang Wencai took his interest in nature all the way to 1_____________. He made 2__________his life. the fields Achievements He 3______________________ about 1370 new plant species in China. He received the First Class Award of the National Natural Science Award 4___________. discovered and named plants twice Spirit He explored China's plants with 5____________________· He 6________________while doing field work in Yunnan, but he never stopped his work. He lost sight in his right eye, but he still 7_____________ his research for another 10 years. He seldom cared about 8______________________. To him, the National Natural Science Award belonged to 9__________. For a long time, even his granddaughter 10____________ about his achievements. great passion and hard work fell seriously ill carried on with personal honour or wealth the team had no idea Answer the questions. 1 What does the writer mean by "made plants his life"? 2 What does "quiet about" mean? Which expression in the passage has a similar meaning? "Quiet about" means not talking much about something (keeping it to himself). A similar expression in the passage is "hardly mentioned it". It means Wang Wencai devoted his entire life to studying and working with plants — plants were the central focus of his life's work and passion. 3 Why does the writer mention “the seasons” in the last paragraph? The writer connects Professor Wang’s life to the seasons (he was born in early summer, passed away in autumn) to compare him to plants—just like plants grow and rest with seasons, his life was closely tied to nature (his lifelong work with plants), which also emphasizes his deep “love of nature” and makes the description more poetic. Think and Share 1 What does the title of the passage mean? A title is not a conclusion, but a summary of the writer's ideas. Thinking from the writer's point of view can help you better understand the title. Learning to think For question 1 It means Wang Wencai dedicated his entire life to studying and working with plants—plants were not just his research subject, but the core of his lifelong pursuit and passion. 2 What words will you use to describe Wang Wencai? Dedicated: He spent over 70 years exploring and researching plants. Persistent: He kept working even after illness, vision loss, etc. Humble: He cared little about personal honor/wealth and was quiet about his achievements. Passionate: He had a deep love of nature and plants. Language Points 1. For over 70 years, he travelled across China to record the country's plants. 六十余年来，他走遍中国各地，记录这个国家的植物。 travel across在此处表示“横穿、穿过或游历某个地区、国家”。 例如: They decided to travel across Europe during their summer holiday. 他们决定在暑假期间横穿欧洲旅行。 She travelled across the United States to visit all the national parks. 为了游览所有的国家公园,她走遍了整个美国。 2. This person was Wang Wencai. 这个人就是王文采。 王文采(1926-2022)，出生于山东济南，原籍山东掖县(今莱州市)，植物分类学家，中国科学院院士，中国科学院植物研究所研究员。 3. To carry out his research, he spent years in wild mountains and forests. 为了开展研究，他在山区和森林中度过了多年的时光。 carry sth out在此处意为“进行……，执行……” 例如: The scientists carried out experiments to test their hypothesis. 科学家们通过实验检验了他们的假设。 We need to carry out a thorough investigation into the matter. 我们需要对这个问题进行彻底的调查。 4. Once, he fell seriously ill while doing field work in Yunnan. 有一次，他在云南进行野外工作时得了重病。 fall ill在此处意为“生病”。例如: She fell ill with the flu and had to stay home for a week.她患上了流感，不得不在家休息一周。 He fell seriously ill and had to be hospitalised.他病得很重，不得不住院治疗。 5. With a magnifier in hand, he carried on with his research for 10 years. 他手拿放大镜，继续他的研究，一干就是十年。 carry on with sth在此处表示“继续某事”。例如: She wants to carry on with her studies. 她想继续完成她的学业。 Her story has given him the will to carry on with his research. 她的故事使他决心继续研究下去。 6. Although he received the State Natural Science Award (First Prize) twice, he hardly mentioned it. 尽管他两次获得国家自然科学奖(一等奖)，但他几乎从未提起过这些。 (1) prize在此处作名词，意为“(给予获胜者的)奖品，奖金，奖 赏"。first prize即一等奖。 (2)国家自然科学奖，是由中华人民共和国国务院设立，由国家科学技术奖励委员会负责的奖项，是中国五个国家科学技术奖之一，授予在基础研究和应用基础研究中阐明自然现象、 特征和规律，做出重大科学发现的中国公民。 7. Instead, they got to listen to Beethoven's Pastoral Symphony. 相反，他们听到的是Beethoven的《田园交响曲》。 (1) get to do sth在此处意为“有机会做某事”。例如: We got to meet all the actors after the show. 演出之后我们见到了所有演员。 She gets to travel all over the world with her job. 她做这个工作可以到世界各地旅行。 (2)路德维希·范·贝多芬(Ludwig van Beethoven,1770—1827)，出生于德国莱茵河畔的波恩，维也纳古典乐派代表 人物之一。 $Ancient people here thought that the sun makes the river hot. It's possible, right? There's a lot of sunshine here. actually. It's unlikely for the sun to heat the river that much. Just think outdoor swimming pols what the water get to eighty six degrees sales in summer? You're right. But how about volcanoes? Perhaps the river passes a volcano and . becomes hot. Good guess, but i'm afraid that's not the reason. The nearest volte is about seven hundred kilometers away. I have another idea. Maybe there are some chemicals in the water. They can produce heat. I've studied them at school. That's possible. But scientists haven't found such chemicals in the yet. They need to do more research. Plants for life. Nature presents us with endless wonders. Most people get interested and ask questions. But one person took his interest all the way to the fields. He was born in the flowering season of early summer and made plants his life. This person was one went side for over seventy years. Professor wong explained china's plants with great passion and hard work. He discovered and named about one thousand, three hundred and seventy new plant species to Carry out his research. He spent years in wild mountains and forests once he fell seriously ill while doing field work in unna. Though he nearly died, wong never stopped his work. He lost site in his right eye at the age of eighty three, but he didn't let anybody know. With a magnifier in hand, he still Carried on with his research for another ten years. Despite his huge success, one seldom thought about personal honour or wealth. Although he received the first class award of the national natural science awards twice, he hardly mentioned IT. For him, the award belonged to the team, and he was just doing his job. In fact, wrong was always quiet about his achievements. He was such a great scientist, but for a long time, even his granddaughter had no idea plants grow and sleep with the seasons. So did professor wong. He passed away at the age of ninety six with the falling leaves of autumn. When people came to say goodbye, they didn't hear any sad notes. Instead, they got to listen to bs. Pastor, this was one's favorite piece of music. IT softly told people about his life, fong, exploration and love of nature. Unit 5 Looking into nature Writing Learning Objectives In this lesson, you will: 1. write a story about a nature explorer. 2.share your writing with your class. Look and Say Do you know the woman in the picture? Jane Goodall (1934-2025) Jane Goodall is a famous scientist from England. She spent many years studying chimpanzees in Africa. She learned important things about how chimpanzees live and behave. She also works hard to protect animals and their homes. ... In 1960, at 26, she went to a Tanzanian forest to study wild chimpanzees. At first, the chimps feared her, and she lived simply in the wild. But with patience, the chimps trusted her—she even found they use tools (like sticks to get food), which changed how people saw animals. Later, she worked hard to protect chimps and nature. She’s kind, patient, and shows us to love and respect the natural world. Write a story about a nature explorer. Step① Think of a story about a nature explorer and complete the table. Who:_________________________________________ When:________________________________________ Where:________________________________________ Jane Goodall In the 1960s Gombe Stream National Park, Tanzania (a wild forest) What happened: 1) What did he / she plan to explore? ___________________________________________________ 2)What difficulties did he / she meet? ___________________________________________________ 3) What was the result? ___________________________________________________ She planned to explore the behavior and lives of wild chimpanzees. At first, the chimps were afraid and ran away. She had to sit quietly for many days to gain their trust. Other scientists doubted her because she was young and had no university degree. Life in the forest was also hard and lonely. She discovered that chimpanzees use tools, have close family bonds, and show emotions like humans. Her work changed how people see animals. She later started the Jane Goodall Institute to protect chimps and forests, and now teaches people around the world to care for nature. What's your opinion of him / her? I think Jane Goodall is brave, patient, and kind-hearted. She followed her dream with passion and showed that with love and perseverance, one person can really help the world. She inspires me to respect all living things. Write the story with the help of the table. Step② Step③ Check. Did you: include the main points of the story in the table in Step 1? use the words and expressions from the reading passage? give your opinion about the spirit of exploration? Step④ Share your story with the class. $ Unit 5 Looking into nature Starting out & Understanding ideas Learning Objectives In this lesson, you will: 1. identify the key information about amber from the passage. 2. learn to analyze the passage’s content, writing style and language 3. share ideas about nature exploration. What does the picture make you feel? The nature is so vast and beautiful while people seem so small in comparison. Look and Say The quiet desert and starry sky make me feel relaxed but a little lonely. ... Look at the pictures and answer the questions. Starting out 1 What do you know about these people? 2 What do they have in common? Li Shizhen was a famous Chinese medical scientist from the Ming Dynasty. He wrote Compendium of Materia Medica(《本草纲目》), a great work on traditional Chinese medicine. Charles Darwin was a British naturalist. He proposed the theory of evolution(进化论), explaining how species change over time. Wang Zhenyi was a talented Chinese female scientist (from the Qing Dynasty). She studied astronomy, mathematics and medicine, and made contributions to these fields. They were all scientists who loved learning about nature. They studied plants, animals, stars, or medicine to help people understand the world better. Look at the picture and answer the questions. 1 What secrets of nature do you know? 2 Which one do you want to explore more? Understanding ideas Look at the title and the pictures. What is the passage about? Use the word cloud to help you. amber 琥珀 The passage is about amber and how it acts as "a window on the past"—it helps unlock the secrets of nature, serving as a key to discoveries that can prove and explain changes in the natural world. 1 Imagine a dinosaur in an ancient forest. It is running around looking for its next meal. With an angry cry, it opens its mouth, raises its beautiful feather-covered arms, and... 2 Wait, feathers on a dinosaur? For hundreds of years, people believed that dinosaurs looked like huge lizards. Just look at all those dinosaurs in books, films and TV shows! However, thanks to a piece of amber, scientists now know that this idea is wrong. In the amber from Southeast Asia, they found the tail of a dinosaur - with feathers. 3 These beautiful golden stones quietly keep pieces of the past. They can tell us whether dinosaurs had feathers, but that's not all. They also help us understand that life on earth has always changed. A piece of amber from Northern Europe, for example, holds a flower. This species no longer grows in this area. But the find proves that it did 35 million years ago. In the future, amber may also help us discover if other species have changed over time. 4 Thanks to amber, more than 300 unknown species have been discovered. In a piece of amber from Africa, scientists found 13 ants. Research shows that they are a completely new species. Scientists used to believe that ants came from the northern half of the earth. The discovery of this African species has changed old beliefs about the history of ants. Who knows whether this piece of amber will tell us more secrets? 5 As a window on the past, amber has been much studied. However, it's still not fully understood. We should put more effort into research. Then we can use this key to unlock more secrets of nature. Choose where you are most likely to read this passage. a in a popular science magazine about findings in nature b in a newspaper report on exhibitions about dinosaurs c in a sci-fi book about travelling 160 million years into the past Complete the diagram with the correct form of the words and expressions from the passage. Amber shows us 1________caught in time. It shows us what ancient species looked like. 2__________a piece of amber, scientists know that dinosaurs had feathers. It helps us understand that life on earth has 3________________. A piece of amber proves that a species of flower grew in Northern Europe 4__________ years ago. secrets Thanks to always changed 35 million More than 300 6_________ species have been discovered. It helps us discover new species. Scientists found a new species of 7_________ in a piece of amber from Africa. Amber is a(n) 8__________on the past, and a key to unlock more secrets of 9_______. unknown ants window nature More comprehensive questions. 1. What is the main idea of the passage? 2. What does the author mean by saying amber is “a window on the past”? The passage mainly introduces how amber helps people to explore the secrets of nature. The author means that amber lets us look directly into ancient times, almost like looking through a window. It shows us real pieces of history — feathers, insects, flowers — preserved inside, so we can see what life was like millions of years ago. 3. What is the main function of the last paragraph? The last paragraph summarize amber's role as a "window on the past" and a "key" to nature's secrets, and suggests we should do more research to unlock more of these secrets. Think and share 1 What do you think of Paragraph 1? Why does the writer begin like this? Learning to think for question 1 Writers have different writing styles.They use different methods to achieve their goals. These goals include making the text alive, making their arguments strong, getting readers' attention, etc. I think it’s interesting. The writer begins with an exciting dinosaur scene to grab the reader’s attention. It makes the topic fun and makes me want to keep reading to learn more. 2 What are some other ways for you to learn about nature's secrets? We can also learn about nature’s secrets by: reading science books or watching documentaries. visiting museums or natural parks. doing experiments or observing plants and animals outside. using the internet to find science videos or articles. Language Points look for sb / sth在此处意为“寻找” 例如: I'm looking for my keys. They are missing.我在找我的钥匙， 它们不见了。 She is looking for a new job with better opportunities.她正 在寻找一份有更好机遇的新工作。 1. It is running around looking for its next meal. 它正在四处寻找下一顿食物。 2. This species no longer grows in this area. But the find proves that it did 35 million years ago. 虽然这个物种不再在这个区域生长。但这个发现证明，它在三千五百万年前曾存活于此。 no longer在此处意为“不再” 例如: We no longer see each other since I moved away.自从我搬 走后，我们没再见过面。 It's no longer a secret.这已经不是秘密了。 3. Scientists used to believe that ants came from the northern half of the earth. 科学家们过去认为，蚂蚁来自地球的北半球。 used to (do)在此处意为“过去经常(发生),曾经”。 例如: I used to play the piano when I was younger.我年轻的时候经 常弹钢琴。 I used to live in the countryside when I was a child.我小时候 住在乡村。 $