初中英语冀教版九年级上册Lesson 29 DNA—The Story of You教学ppt课件

设计说明

首先，通过父母和子女的图片逐渐引入本课话题——DNA。之后，结合例句和图片学习本课单词，并检测。课文学习：先通过听并跟读，大致了解课文内容，然后分两部分精读学习，通过设置的问题让学生达到对课文内容的理解，之后再读课文并巩固课文中的重点短语。接下来讲解课文中的重要知识点，并指导学生完成Let’s Do It!No.2和No. 3的练习。之后针对Let’s Do It!No.3进行小组讨论，输出所学内容。最后，通过当堂达标的习题检测学生的掌握情况。

教学目标

通过本课节的教学，学生达成以下目标：

1. 知识目标

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. 能力目标

能读懂关于DNA的文章。

3. 情感目标

培养对生命科学的兴趣。

重点难点

1. 重点：掌握本课节的重点单词、短语和句型。

2. 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。

授课时数

1课时

教学过程

Step 1  Warming up

Show 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 reading

Play 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 points

1. In general, a blueprint is a drawing that shows how to put a house together

with 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but

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  Exercises

1. Let students fill in the blanks with the phrases in the box. (Let’s Do It! No.2)

1. 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 to

2. 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?

Answers: A, C, B

Step 7  Talking about

Let 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.

Step 8  Homework

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.

当堂达标

Ⅰ.根据汉语意思完成句子

1. 轻工业和农业密切相关。

    Light industry is closely_________ _______ agriculture.

2. 除了窗户小以外,这座房子很漂亮。

    The house is beautiful ______ _____ the small windows.

3. 你的头发和皮肤有同样的DNA。

    Your hair has ______ _______ _______ _____ your skin.

4. 她不但会唱歌，而且会跳舞。

    She can _____ ______ sing ______ ________ dance.

Ⅱ. 单项选择

1. — Lisa, how is your cousin?

  — He is _________ now. Thank you.

    A. more healthier   B. much healthier

    C. very healthier   D. healthiest

2. There are ________ stars in the sky.

    A. billion     B. billion of

    C. billions            D. billions of

3. Ms. Wang is very strict with us. She always asks us to do everything according to her _______.

    A. attention       B. information

    C. direction           D. instruction

答案: Ⅰ. 1. related to  2. except for  3. the same DNA as  4. not only, but also

Ⅱ. 1—3 BDD

板书设计

教学反思