Unit 5 A delicate World-Understanding ideas 教案-2025-2026学年高中英语外研版选择性必修第二册

Unit 5 A delicate World-Understanding ideas 内容导航 This section takes Macquarie Island as the case, telling the tragic story of its ecosystem destruction by human activities and the subsequent recovery process. It guides students to realize the fragility of nature and the importance of protecting the ecological balance between humans and nature. 教学目标和重难点 1. 教学目标 Language Ability: Students master core words and sentence patterns related to ecology, and improve their ability to read and understand narrative and expository texts. Cultural Awareness: They recognize the global significance of ecological protection, establish the concept of harmonious coexistence between humans and nature, and enhance cross-cultural environmental protection awareness. Thinking Quality: They develop logical thinking by sorting out the cause-effect relationship of ecological changes and critical thinking by evaluating human behaviors. Learning Ability: They learn to use reading strategies to obtain key information and cultivate autonomous and cooperative learning habits. 2. 教学重难点 Key Points: Mastering core vocabulary such as multiply, explode, decrease, trap and key sentence patterns like it-emphatic structure and nor-inversion; understanding the development clue of the text and the theme of ecological protection. Difficult Points: Accurately using the learned words and sentence patterns in specific contexts; deeply understanding the cause-effect relationship between human activities and ecological changes; translating the awareness of ecological protection into practical thinking and behaviors. 教学过程 Step 1: Lead-in (Warm-up & Activation) Activity 1: Visual Aids Presentation The teacher shows students two groups of pictures: one group is the beautiful scenery of Macquarie Island, with blue sea, green grass and various seabirds; the other group is the desolate scene of the island after ecological destruction, with withered plants, soil erosion and scattered garbage. Then the teacher asks two questions: “What do you think of these two pictures? What may have caused the great change of the island?” Activity 2: Vocabulary Preview The teacher presents 5 core words related to the text on the screen: multiply, explode, decrease, trap, ecological. For each word, the teacher provides a simple definition and a sentence related to ecological environment, and guides students to read after the teacher to be familiar with the pronunciation and meaning. For example, “Multiply means to increase quickly in number. Rabbits multiply rapidly if there is enough food.” Then the teacher asks students to work in pairs to make simple sentences with these words, and invites 2-3 pairs to share their sentences. Design Intention: The visual contrast of pictures can quickly attract students' attention, arouse their emotional resonance, and naturally lead to the theme of ecological protection. Previewing core vocabulary in advance helps students remove language obstacles in reading, lays a foundation for smooth understanding of the text, and cultivates their ability to use vocabulary in context. At the same time, pair work can stimulate students' participation and create a positive classroom atmosphere. Step 2: Pre-reading (Prediction & Background Introduction) Activity 1: Title and Picture Prediction The teacher shows the title of the text “A Tragedy on Macquarie Island” and the picture in the textbook (the scene of Macquarie Island). Then guide students to predict: “From the title and the picture, what do you think the text will talk about? Who or what may be involved in the tragedy? What kind of tragedy will it be?” Students are allowed to express their opinions freely, and the teacher does not give correct or wrong judgments, but only records the key points of their predictions. Activity 2: Background Briefing The teacher briefly introduces the background of Macquarie Island in simple English: “Macquarie Island is an isolated island in the Southern Ocean. It is famous for its unique ecosystem and is listed as a World Heritage Site. However, human activities have brought great damage to this delicate island. Today, we will read the story of its ecological changes.” At the same time, the teacher supplements a simple map of Macquarie Island to help students establish a spatial concept. Design Intention: Predicting based on the title and pictures can cultivate students' reading prediction ability, which is an important reading strategy. It can make students have a clear reading goal and improve their reading efficiency. The brief background introduction helps students understand the background of the text, narrow the distance between the text and themselves, and lay a foundation for in-depth understanding of the theme of the text. Step 3: While-reading (Comprehension & Analysis) Activity 1: Skimming for Main Idea The teacher asks students to read the text quickly (skimming) and answer two questions: 1. What is the main idea of the text? 2. What is the development clue of the text? After students finish reading, the teacher invites several students to share their answers, and then summarizes: The text mainly tells the process that Macquarie Island's ecosystem was destroyed by human-introduced species and then recovered through human protection. The development clue is time order and cause-effect order. Activity 2: Scanning for Key Information The teacher asks students to read the text again (scanning) and fill in the following table, which is displayed on the screen: Time Human Activities Impacts on the Ecosystem 1810 Humans arrived on the island and introduced rabbits and cats. Rabbits multiplied rapidly, ate native vegetation and caused soil erosion; cats preyed on native birds. Subsequently Humans introduced a virus to control the rabbit population. Rabbit population decreased, but cats lost food and preyed more on birds; some native bird species became extinct. In the 1980s Humans launched a program to remove introduced species. The ecosystem began to recover; native plants and birds returned. Students complete the table independently first, then check with their deskmates. The teacher walks around the classroom to provide guidance for students who have difficulties. Finally, the teacher invites a student to present the completed table and corrects and supplements it. Activity 3: Close Reading for Details and Language Points The teacher guides students to read the text paragraph by paragraph, focusing on key sentences and language points, and helps students understand the text in depth. Paragraph 1: The teacher asks students to find the it-emphatic sentence: “It's a tragic story that began in 1810 when humans arrived on the island.” Then explain the structure of it-emphatic sentence: “It is/was + the emphasized part + that/who + other parts.” And give an example: “It was Tom who helped me yesterday.” Then ask students to make 2-3 sentences with this structure. Paragraph 2: Focus on the word “multiply” and the sentence “Loose on the island, they did what rabbits do best—they multiplied rapidly and began eating the native vegetation and digging holes, which caused soil erosion.” The teacher explains that “multiply” here means “to increase quickly in number”, and the non-restrictive attributive clause “which caused soil erosion” modifies the whole preceding sentence. Then ask students to analyze the cause-effect relationship in this paragraph: rabbits multiplied rapidly → ate native vegetation and dug holes → caused soil erosion. Paragraph 3: Focus on the word “explode” and the sentence “The rabbit population exploded, and cats, which were introduced to control the rabbits, began to prey on the native birds.” The teacher explains that “explode” here means “to increase suddenly and rapidly”, which is similar to “multiply” but more intense. Then guide students to think: Why did cats prey on native birds? (Because the rabbit population was too large, and cats were introduced to control them, but they also preyed on birds.) Paragraph 4: Focus on the word “decrease” and the nor-inversion sentence “Nor did it save the birds.” The teacher explains the usage of “decrease” (v. to become smaller in number or amount) and the nor-inversion structure: “Nor + auxiliary verb/be verb/modal verb + subject”, which means “neither/nor”. For example: “I don't like coffee, nor does my sister.” Then ask students to translate this sentence and make a sentence with the nor-inversion structure. Paragraph 5: Focus on the word “trap” and the sentence “The cats, trapped without enough food, began to eat more birds.” The teacher explains that “trap” here is a past participle used as an attributive, meaning “caught in a difficult situation”. Then guide students to understand the logic of this paragraph: virus killed rabbits → cats had no enough food → ate more birds → some bird species became extinct. Paragraph 6-7: Guide students to find the measures taken by humans to protect the ecosystem: “In the 1980s, the Australian government launched a program to remove all introduced species from Macquarie Island.” And the results: “Today, the island is recovering. Native plants are growing again, and birds are returning.” Then ask students to think: What can we learn from this process? Design Intention: Skimming helps students grasp the main idea of the text quickly, which is an important reading strategy to improve reading efficiency. Scanning enables students to accurately find key information, sort out the development context of the text, and cultivate their ability to extract and sort out information. Close reading helps students understand the details of the text, master key language points, and deeply analyze the logical relationship in the text. At the same time, through explaining and practicing language points, students' language ability is improved, and the connection between language learning and text understanding is realized. Step 4: Post-reading (Discussion & Application) Activity 1: Group Discussion The teacher divides students into groups of 4-5, and puts forward the following discussion topics: 1. What mistakes did humans make on Macquarie Island? What are the consequences of these mistakes? 2. Why is the ecosystem of Macquarie Island so delicate? 3. What can we learn from the ecological recovery of Macquarie Island? 4. What should we do in our daily life to protect the ecological environment? Each group chooses one topic to discuss in detail. The teacher walks around the classroom to guide students' discussion, reminds them to use the words and sentence patterns learned in the text, and records the key points of each group's discussion. After the discussion, each group sends a representative to make a 2-3 minute report, and other groups can ask questions or supplement. Activity 2: Vocabulary and Sentence Pattern Practice The teacher designs two practice tasks on the screen: Task 1: Fill in the blanks with the correct form of the words given (multiply, explode, decrease, trap, ecological). 1. The number of pandas in China has been ______ in recent years. 2. When the flood came, many people were ______ in their houses. 3. The population of this city ______ in the past ten years, from 1 million to 3 million. 4. We should pay more attention to ______ protection to protect our earth. 5. Rabbits can ______ very quickly if they have enough food. Task 2: Rewrite the following sentences using the it-emphatic structure or nor-inversion structure. 1. Humans' wrong behaviors caused the ecological destruction of Macquarie Island. (it-emphatic structure) 2. I don't know the importance of ecological protection, and my friend doesn't know it either. (nor-inversion structure) Students complete the tasks independently, then check the answers with the teacher. For the wrong answers, the teacher explains the reasons and helps students correct them. Activity 3: Theme sublimation The teacher makes a summary: “Macquarie Island's story tells us that the ecosystem is very delicate. Human activities can easily destroy it, but with positive efforts, we can also help it recover. Protecting the ecological environment is not only the responsibility of each of us, but also the key to the sustainable development of human beings. We should establish the concept of harmonious coexistence between humans and nature and take action to protect our beautiful home.” Then the teacher plays a short video about global ecological protection, showing the beautiful scenery of nature and the current ecological problems, which further strengthens students' awareness of ecological protection. Design Intention: Group discussion can cultivate students' cooperative learning ability and oral expression ability, and enable them to deeply understand the theme of the text through communication and exchange. Vocabulary and sentence pattern practice helps students consolidate the knowledge learned, improve their ability to use language flexibly, and realize the application of knowledge. Theme sublimation helps students raise their awareness of ecological protection, establish correct values, and realize the infiltration of cultural awareness and thinking quality. The short video can enhance the emotional impact and make the theme of ecological protection more deeply rooted in students' hearts. Step 5: Consolidation & Extension Activity 1: Text Retelling The teacher asks students to retell the story of Macquarie Island with the help of the key information in the table filled in during the while-reading step. Students can retell it individually or in pairs. The teacher requires students to use the words and sentence patterns learned in the text as much as possible, and pays attention to the logic and fluency of the retelling. After retelling, the teacher gives comments and guidance, affirming the advantages and pointing out the deficiencies. Activity 2: Extended Reading The teacher provides a short passage about another ecological protection case (such as the protection of the Giant Panda Reserve in China) and asks students to read it after class. The passage is designed with 3 simple questions to help students understand the main content. The requirements are: 1. Read the passage carefully and answer the questions. 2. Find the key words and sentence patterns related to ecological protection in the passage. 3. Compare this case with the case of Macquarie Island and write a short comment (about 50 words). Activity 3: Homework Arrangement The teacher assigns three homework tasks: 1. Recite the core words and key sentences learned in this lesson. 2. Complete the extended reading task after class. 3. Write a short passage (about 100 words) about “My Contribution to Ecological Protection”, using the words and sentence patterns learned in this lesson. Design Intention: Text retelling helps students consolidate the content of the text, improve their oral expression ability and logical thinking ability, and deepen their understanding of the text. Extended reading can expand students' horizons, enable them to contact more ecological protection cases, and further strengthen their awareness of ecological protection. Homework arrangement is an extension of classroom teaching, which helps students consolidate the knowledge learned, apply the language knowledge to writing, and realize the integration of listening, speaking, reading and writing. Step 6: Summary & Reflection Activity 1: Classroom Summary The teacher invites students to summarize what they have learned in this lesson, including the main content of the text, key words and sentence patterns, and their understanding of ecological protection. Then the teacher makes a comprehensive summary, emphasizing the key and difficult points of this lesson, and reviewing the learning objectives. Activity 2: Student Reflection The teacher asks students to think about two questions: 1. What have I learned in this lesson? What have I mastered? 2. What difficulties do I still have? What should I do to improve? Students can write down their reflections in their notebooks, and the teacher collects some notebooks to check and understand students' learning situation, so as to adjust the teaching plan for the next lesson. Design Intention: Letting students summarize the lesson by themselves can cultivate their ability to sort out and summarize knowledge, and enhance their sense of learning initiative. Student reflection helps students understand their own learning situation, find their own deficiencies, and make targeted improvements. At the same time, the teacher can understand students' learning effect through checking the reflection, which provides a basis for optimizing the teaching process. 1 / 1 学科网（北京）股份有限公司 学科网（北京）股份有限公司 学科网（北京）股份有限公司 $