译林版（2019）必修 第三册Unit 1 Nature in the balance Reading (II) 教学设计

Unit 1 Nature in the balance
Reading (II)（教学设计）
I. Learning objectives
By the end of the lesson, students will be able to:
1. understand the usage of the following words and expressions: a huge sea of, alive with, play a significant role in, including, variety, while, a number of, survive, in turn, impact;
2. use the above words and expressions in new situations;
3. understand the negative prefixes un-, dis-, in-/im-/il-/ir-, non-;
4. present figures by making comparisons with familiar places or objects.
II. Key competence focus
1. Understand some new words and expressions.
2. Use the new words and expressions in new situations.
III. Predicted area of difficulty
Use the new words and expressions in new situations properly and correctly.
IV. Teaching procedures
Step 1 Lead-in
T asks Ss to review the documentary script by completing a summary. T shows Ss the structure and some keywords to help them summarize the text.
T: Hello, everyone! In the first period of this unit, we’ve learned a documentary script about the Amazon rainforest. Today we’ll review the text, appreciate the language in it, discuss how to use some of the words and phrases, and practise using them in new situations.
T: Would you please summarize the text according to the following keywords
Size: the largest rainforest in the world; an area of around 6 million square kilometres
Plant species: more than 40,000; different levels
Species of birds and mammals: more than 1,300 species of birds and over 400 species of mammals; jaguars and the food chain
Values: fixes carbon and produces over 20% of all the Earth’s oxygen; a treasure house of species
Threats: 17% of the rainforest lost due to human activities
【设计意图：回归课本，教师给出语言支架，要求学生概括文章内容，帮助学生回忆前一日所学文章内容；培养学生的语言概括能力，为概要写作打下基础。】
Step 2 Group work
T assigns the 5 paragraphs of the text to 5 different groups.
T: Do you have any difficulties in reading the documentary script, including the words, phrases and sentences, etc Now, we’ll work in groups to discuss and share our learning notes.
【设计意图：让学生找出语篇的语言重难点，鼓励学生开展自主学习和小组合作学习，借助词典等工具书解决疑惑拓展新知，培养学生的学习能力，为下一步讲解语篇中重点语言知识做准备。】
Step 3 Language comprehension and extension
T asks Ss to present their difficulties on the blackboard and share their learning notes. During their presentations, T makes necessary extension.
T: Now, let’s welcome some students to share what they have got by studying individually and cooperatively.
Paragraph 1
(1) Welcome to the jungle, a huge sea of green alive with the sounds of animals. (page 2, line 1)
A huge sea of: a lot of, plenty of
Alive with: be full of things that are alive
T: Now, boys and girls, please translate the following sentences.
(2) As the largest rainforest in the world, it plays a significant role in maintaining the fine balance of the Earth’s ecosystem. (page 2, lines 2–3)
T: Can you guess the meaning of play a significant role OK, let’s look at an example.
Paragraph 2
(1) The Amazon rainforest crosses into eight countries, including Brazil and Peru, and one overseas region of France, all on the South American continent. (page 2, lines 4–5)
T: Boys and girls, do you know the part of speech of including What does it mean What are its verb form and adjective form Let’s look at some examples.
(2) The Amazon River, from which the rainforest gets its name, is close to 6,400 kilometres in length—roughly 100 kilometres longer than the Yangtze River. (page 2, lines 7–9)
Analysis of the relative clause
T: What kind of relative clause is it What is it introduced by Can you give more examples
Presenting figures by making comparisons with familiar places or objects
T: In this sentence, we can learn the writing technique of presenting figures by making comparisons with familiar places or objects. While the reader may find a large figure too abstract to understand, making comparisons with familiar places or objects will help them gain a better understanding. Here are some expressions that can be used to make comparisons: the same size/length as …, more than/larger than/longer than …, as large/long as, twice/three times as large/long as …
T: The documentary script compares the size of the Amazon rainforest with that of China, and the length of the Amazon River with that of the Yangtze River. Can you find the the comparisons in the documentary script
T: Now, please use the following information to make comparisons to make these figures in these sentences easier for readers to understand.
3. Paragraph 3
(1) This tall and ancient brazil nut tree produces nuts that we can eat; these water lilies are big enough to lie down on. (page 3, lines 13–14)
T: Boys and girls, can you translate this sentence What kind of relative clause is it What is it introduced by Now let’s look at more examples.
(2) The forest’s different levels support an unbelievable variety of wildlife. (page 3, lines 14–15)
The usage of variety
T: Look at the sentence from paragraph 3. What’s the meaning of variety here Do you know the verb form and the adjective form of variety
The usage of negative prefixes to express the negative meanings of adjectives or verbs
T: Boys and girls, please pay attention to the word unbelievable. How is it formed It is formed by adding the negative prefix un- to the adjective believable. Here are more negative prefixes: dis-, in-/im-/il-/ir-, non-. Would you please list as many similar words as possible
T: Now please fill in the blanks with words with negative prefixes.
4. Paragraph 4
(1) While a significant number of jaguars survive here, there are only one element of this forest’s food chain. (page 3, lines 23–24)
T: Can you understand the underlined words and phrases in the sentence
While: although; despite the fact that
T: Please explain the meanings of while in these sentences.
A significant number of: a lot of
T: Pay attention to the difference of a number of and the number of. Then fill in the blanks.
Survive: to continue to live or exist despite a dangerous event or time
T: Match the sentences with the correct meanings of survive, survival or survivor.
(2) These frogs, in turn, feed on insects which eat leaves and fruit. (page 3, lines 25–27)
T introduces the collocations of turn and asks Ss to fill in the blanks.
T: Now, let’s look at the sentences and fill the blanks with the words in the box.
5. Paragraph 5
As the impact of human activities continues to grow and the list of species in danger of extinction becomes longer, we are left with a question: can we afford to damage the “lungs of the planet” (page 3, lines 35–38)
Impact as a noun
T: Look at the sentence from paragraph 5. What’s the meaning of impact here Do you know other meanings of impact Can you guess the meaning of impact in the following sentence “The impact of the stone against the windowpane shattered the glass.”
Impact as a verb
T: Impact can also be used as a verb. For example: “Her father’s death impacted greatly on her childhood years.” Boys and girls, can you translate this sentence into English
【设计意图：结合主题语境，深度挖掘文本，通过阅读文本来梳理重要语言知识，包括词汇和长难句等，培养学生学习能力。在语言知识拓展环节中，不断创设新的语言情境，鼓励学生从不同的情境中获得新知，通过梳理、概括、整合信息，建立信息间的关联，形成新的知识，并学会应用到新的情境中去，达到对文本重点语言知识的理解和运用，为下一步语言知识在新语境中的运用打下基础。】
Step 4 Consolidation
T asks Ss to translate some sentences into English, using the words and phrases in the brackets.
长江是世界上第三大河，它几乎和亚马孙河有相同的长度。(the same length as)
The Yangtze River is the third largest river in the world, which almost has the same length as the Amazon River.
长江流域面积有180万平方千米，流经中国八个省、两个直辖市和一个自治区。(with an area of)
With an area of 180 million square kilometres, the Yangtze River crosses into eight provinces, two municipalities and one autonomous region of China.
长江在维持中国的生态平衡中扮演着重要的角色。(play a significant role in)
The Yangtze River plays a significant role in keeping the balance of the ecosystem in China.
长江维系着许多不同的生态系统，许多珍稀动物都能在这里找到。(a variety of)
The Yangtze River supports many different ecosystem and a variety of rare animals can be found here.
然而，由于人类活动的影响，一些珍稀动物消失了。(the impact of ...)
However, because of the impact of human activities, some rare animals have disappeared.
这些动物是不可替代的，我们应该采取措施来保护它们。(irreplaceable)
These animals are irreplaceable and we should take some measures to protect them.
【设计意图：让学生的关注点从亚马孙河、亚马孙热带雨林转移到长江以及长江流域，在新的语境中应用本课知识点。】
V. Homework
1. Look up in the dictionary or a reference book to find out more words formed with negative prefixes.
2. Finish part B1 on page 5 of the textbook.
3. Write a short passage to introduce the Yangtze River using what we have learnt in class.