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Unit 5 Look into Science
课时 Lesson 29: DNA—The Story of You 课型 新授课
教学目标 1. 语言能力掌握单词：general, repeat, grandson, granddaughter, instruction接触单词：DNA, blueprint, complex, twin, pattern, identify, related短语和句型： in general, except for, be related to, billions of From your DNA, scientists can identify not only you, but also people who are related to you.2. 学习能力能读懂关于DNA的文章。3. 思维品质培养对生命科学的兴趣。
教学重点 掌握本课节的重点单词、短语和句型。
教学难点 能够读懂关于DNA的文章。
教学准备 PPT 课件；本课节用到的音频。
教 学 过 程 Step 1 Warming upShow students a picture and talk with students like this: T: Look at the picture. What you find Ss: The boy looks like his father. The girl looks like her mother. T: Why do they look the same Ss: We don’t know. T: Because your DNA comes from your parents.T: What do you know about DNA Ss: …T: This is the shape of DNA. Today we’ll learn about it.Step 2 Presentation 1. Teach the new words complex, identify, related, grandson, granddaughter, twin, repeat, pattern, blueprint and instruction and expressions in general, except for, be related to, with the help of pictures and sentences. 2. Let students try to write the following words.(1) 复杂的　　 adj. complex(2) 双胞胎之一 n. twin(3) 重复; 复述; 背诵 v. repeat (4) 模式; 形式 n. pattern(5) 确认; 鉴别 v. identify (6) 指示; 说明 n. instruction(7) 孙子，外孙 n. grandson(8) 孙女，外孙女 n. granddaughter(9) blue 意为“蓝色”, print意为“印刷品”, 其合成词blueprint, 意为“蓝图”。(10) general为形容词, 意为“总的; 普遍的”; 其副词形式为“generally”。 Step 3 Listening and readingPlay the recording of the passage for the class to listen and ask them to read after it.Step 4 Reading 1. Get the class to read the first part of the passage and answer the questions.(1) What is a blueprint (2) What is the blueprint of life (3) Which is more complex, building a living thing or building a house Why (4) Before we are born, what can be influenced by our DNA Answers: (1) It’s a drawing that shows how to put a house together with many different parts. (2) DNA.(3) Building a living thing is far more complex than building a house.Because it takes millions of years for nature to change the DNA in living things to make them fit the world they live in. (4) Our height, the colour of our eyes, the size of our feet.2. Get the class to read the second part of the passage and answer the questions. (1) Do some twins have the same DNA (2) Is your hair has the same DNA as your finger (3) Is it possible to change your DNA (4) Whose DNA is related to yours Answers: (1) Yes, they are. (2) Yes, it is. (3) Yes, it is. In the future, scientists might be able to change my DNA.(4) People who are related to me. For example, my parents and grandparents.3. Get the class to read the passage again and find the following phrases in the passage, then translate them. (1) in general 一般而言，通常 (2) except for 除……之外 (3) be caused by 由……引起 (4) not only… but also… 不但……而且…… (5) be related to 与……相关 (6) billions of 数十亿的 Step 5 Language points1. In general, a blueprint is a drawing that shows how to put a house togetherwith many different parts. 一般而言，蓝图就是一幅图纸，它显示一座房子的构造。in general意为“一般而言，概括说来”,通常置于句首，也可以用generally speaking来表示。In general/Generally speaking, women cry more easily than men. 一般而言，女人比男人容易哭。2. But building a living thing is far more complex than building a house.但创造一个生物比盖房子要复杂得多。far用来修饰形容词和副词的比较级，这样的词语还有much, still, even, no, a little, a bit, a lot, rather, any等。The room is a bit larger than that one. 这个房间比那个稍大一点。He works still harder than ever. 他比以往更加努力学习了。Matters are a lot better than ever before. 情况远远比以往好。Can he jump any higher 他能跳得更高一些吗？Lesson One is much easier than Lesson Two. 第一课比第二课容易得多。Tom looks even younger than before. 汤姆看上去甚至比以前还年轻。This train runs much faster than that one. 这辆火车比那辆快得多。3. Except for some twins, every living things has its own unique DNA.除了同卵双胞胎之外，每个生物都有自己独特的DNA。辨析：except (for), besides与butexcept (for)除……之外except (for)后所跟的内容是被排除的部分，不同类的besides除之外(还有……)besides后所跟的内容也包括在整体中but除……之外(什么也没有)but后所跟的内容是仅有或仅存的，通常与nothing, nobody, no等否定词连用He is a good man except for the hot temper.他是一个好人，只是脾气暴躁。Two other boys are on duty today besides you.包括你在内还有两名男孩今日值日。(共三人)There is nothing but a desk in the room.房间里除了一张桌子外什么也没有。4. From your DNA, scientists can identify not only you, but also people who are related to you. 从你的DNA中，科学家们不但能够辨认出你，而且能够辨认出和你有血缘关系的人。(be) relate to / with 表示“与……有关”。He is related to my family. 他与我的家庭有关系。【拓展】relate动词，意为“把……联系起来”。The matter relates to him.这事与他有关。I can’t relate what he does with what he says.我无法把他的言行联系起来。Step 6 Exercises1. Let students fill in the blanks with the phrases in the box. (Let’s Do It! No.2)in general except for not only… but also related to even if the same … as1. Your homework is quite good _________ a few spelling mistakes.2. ________ the young _______ the old like pop music. 3. Kate’s hair is _________ colour _______ her sister’s.4. __________, women live longer than men.5. _______ many difficulties remain, we can overcome them.6. Is wealth _________ happiness Answers: 1. except for 2. Not only, but also 3. the same, as 4. In general 5. Even if 6. related to2. Let students complete the passage with the sentences in the box. (Let’s Do It! No.3)Changing DNA Do you know DNA can be changed Have you ever seen a pig with a dog’s body Of course not! Pigs and dogs can’t have babies together. _______ But now, scientists can do it. Scientists can take DNA from one kind of animal and put it into another kind of animal. They can design new plants by combining the DNA of other plants. ________ Some scientists are worried. They say we need to know more about DNA before we start changing it. ________ But what if the plants are bad for humans, too A. Their DNA can’t combine.B. We can make plants that are bad for pests.C. They can even combine the DNA of a plant and an animal.Answers: A, C, BStep 7 Talking aboutLet students talk about the following questions in their group. (Let’s Do It! No.4) Is it a good idea to change the DNA of the food we eat Some people say doing this makes our food better. Others think it’s too dangerous. Search the Internet for information and write down your ideas.
课堂作业 1. Recite the new words and expressions.2. Try to write a short passage about: Is it a good idea to change the DNA of the food we eat 3. Preview Lesson 30.
板书设计 UNIT 5 Look into ScienceLesson 29: DNA—The Story of Yougeneral, repeat, grandson, granddaughter, instructionDNA, blueprint, complex, twin, pattern, identify, relatedin general, except for, be related to, billions of

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