Unit 5 Look into ScienceLesson 29 DNA-The Story of You 教材分析1. Analysis of the Students The students of Grade 9 have mastered certain vocabularies，expressions and structures. They also have the abilities of self-teaching and working in groups. Most of them are willing to express their opinions in English.2. Analysis of Teaching ContentLesson 28 is the fifth lesson in Unit 5, Book 5.This unit focus on the subject Look into science, also teach the students something about science. Students cares about the subject because it is close to everyone. Lesson 28 mainly talks about DNA, it tell us the character and function of DNA, also understand our body. We are unique in the world. 教学目标【知识目标】1. To master the words: blueprint, general, complex, twins, pattern, identify, be related to, except for.2. To master the phrases: not onlybut also, except for, be related to, billions of.【能力目标】Improve the students ability of speaking, listening, reading and writing. Understand the articles about DNA.【情感目标】Know more about the nature, know more about our body. You are unique in the world.【教学重点】To master the compound sentences.【教学难点】To master the use of DNA. 课前准备 Tape recorder, Multimedia 教学过程Step 1. Warm-upFree talk: (show the picture of DNA, tell students DNA is short for deoxyribonucleic acid.)Think about it!1. What do you know about DNA?2. What can scientists do with DNA?Step 2. Presentation1. Free talk: (1) Where is it in our body? (Show some pictures of DNA.)(2) Whats the function of DNA? (Show some pictures of twins.)2. Explain the new words.3. Read the lesson and answer the questions：(1) What is a blueprint?(2) Which is more complex, building a living thing or building a house?(3) Do some twins have the same DNA?(4) Is it possible to change your DNA?(5) Whose DNA is related to yours?4. Check the answers and underline the key words.5. Listen and follow to the tape.6. Explain the language points:between与amongbetween用于两者之间，among一般指三者或三者以上。Jack sits between Tim and Bob. Jack坐在Tim和Bob之间。She was among the crowd. 她处在人群中。useto do sth. 用做某事She is using a knife to cut vegetables. 她正用小刀切蔬菜。 use的形容词是useful.Is the fridge very useful? 这台冰箱很有用吗？too与either too与either都表示“也”，其区别是too用于肯定句，表示“也”；either用于否定句，表示“也不”。他们通常都位于句末，其前用逗号隔开。He has a baby brother, too. 他也有个小弟弟。He doesnt have an eraser, either. 他也没有橡皮。own的用法adj. 自己的（用在所有格后面，加强语气） He makes all his own notebooks. 她所有的衣服都是自己做的。vt. 有；拥有 Who owns the car? 这辆汽车是谁的？owner n. 所有人；物主She is the owner of the house. 她是这座房子的主人。except for除以外，只是David is a good man except for hot temper. 大卫除了脾气暴躁以外，他是个好人。The classroom is nice except for dirty on the floor.教室除了地板脏以外都很好。Step 3. Practice1. Read the lesson by themselves.2. Fill in the blanks with the phrases in the box on page 75. in general, except for, not onlybut also, related to, even if, the sameas(1) Your homework is quite good_ a few spelling mistakes. (2) _the young_ the old like pop music. (3) Kates hair is_ colour _her sisters. (4) _,women live longer than men. (5) _many difficulties remain, we can overcome them. (6) Is wealth_ happiness? 3. Check the answers.4. Ask students: Do you think DNA can change each other? Read again and Complete the passage with the sentences in the box.Changing DNADo you know DNA can be changed? Have you ever seen a pig with a dogs body? Of course not! Pigs and dogs cant 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 cant combine.B. We can make plants that are bad for pests.C. They can even combine the DNA of a plant and an animal.5. Check the answers.Step 4. ConsolidationGroup work: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 its too dangerous. 1. Discuss the idea of yours.2. Write down your ideas.3. Report you ideas.Step5 Homework1. Listen and read.2. Finish exercises of this lesson. 教学反思略。