Ⅰ．Teaching aims and demands:

1.Knowledge aims

1).Learn new words and phrases.

sand, just now, sandstorm

cut down, change into, desert

prevent … from, human being,

although.

2).Learn to talk about kinds and

harm of pollution.

2.Ability aims

培养学生合作交流，自主学习的能力。

3.Emotions

Increase students’ awareness of protecting  environment.

Ⅱ．Teaching  procedure:

1．小组合作学习：

  1).小组交流讨论学案。

  2).分配展示任务。

2.  分组展示

  1）板演任务。

  2）分组讲解任务。

学生展示时,教师须点拨的问题

Task 1

若出现发音不准的情况，教师需做出正确的示范.

Task 2

注意学生的语音语调是否准确,

学生进行自由对话时教师以鼓励和表扬为主。

Task 3

引导学生作出完整的回答

(1)They are talking about air pollution.

(2)Trees.

(3)Yes，it is.

学生还有可能提到的问题有：

(1)How can trees affect the weather?

(2)Have we built the Great Green Wall?

Task 4

1. cut down 砍倒

e. g: Don't cut down any trees.

注意：cut的现在分词为cutting,

过去式和过去分词均为cut.

2.although 虽然，尽管

e. g: Although he is very tired,

he goes on with his work.

注意：although 不与but 连用,后可接yet 或still.

Task 5

 1. A lot of rich land has changed into desert.

 a  lot  of 很多的,大量的

e. g: I have a lot of homework to do today.

change  into 改变,变成

e. g: You can’t change iron into gold.

2.Trees can stop the wind from blowing the earth away. … They can also prevent the water from washing the earth away.

stop/prevent/keep sb./sth. from doing sth. 阻止某人/某物做某事

e. g: I tried to stop/prevent my son (from) playing computer games.

Task 6

Trees can prevent the water from washing the earth away.

4．反馈

学生独立完成练习后交流结果。

5．小结：

学生小结后教师归纳总结。

Ⅲ。教学反思：

课题：Unit 2  Topic 2  Section  B

All these problems are very serious.

课型:预习+展示

Learning  procedure :

1. Try to read the following sentences. Find out and underline the new words and phrases. Read aloud and remember.

(1)What causes the sandstorms?

(2)What did he do just now?

(3)Cutting down trees is harmful to human beings.

(4)A lot of rich land has changed into desert.

(5)They can prevent the water from washing the earth away.

(6)Although she doesn’t have a lot of money, she still feels very happy.

2. I can read .

Try to read 1a . Pay attention to pronunciation.

3. I can say.

 Can you have a free-talk according to 1a?

E g .A: Do you know why there are so many sandstorms all over the world ?

B: It’s said that the natural environment has been destroyed. A lot of rich land has changed into desert, leaving only sand. So the wind blows with sand. It forms sandstorms.

A: How do trees affect the weather?

B: Trees can stop the wind from blowing the earth away. They can also prevent the sand from moving toward the rich land.

A: Have we built the Great Green Wall to prevent the earth and water from running away.

B: Yes, but we still need to work hard to protect the environment.  

4. Can you answer?.

Read 1a and answer the questions.

(1) What kind of pollution are they talking about?

 (2) What can stop the wind from blowing the earth away?

(3) Is cutting down trees harmful to human beings?

Do you have any other questions according to 1a?

5. I can analyze(分析).

 Read and underline the phrases and the important sentences in 1a.

E g (1) A lot of rich land has changed into desert.

   (2) Trees can stop the wind from blowing the earth away.

Can you find out any other language points in 1a?

6. Can you finish 1b?

 E g : (1)A lot of water can be saved by forest.

(2) Trees can stop the wind from blowing the earth away.

7.  I can do.

当堂检测 , 通过1a的学习，我能完成与之有关的英汉互译。

 What causes the sandstorms, do you know? Now let me tell you. You know all over the world people have cut down many trees every year. Trees are becoming fewer and fewer. (1)大量肥沃的土地变成了沙漠。                                                                                                                                                                 

So sandstorms happen when the wind is blowing strongly. Now we must plant trees! The more, the better. (2)Trees can stop the wind from blowing the earth away.                                                       (3)森林可以储藏大量的水分。                             Ⅰ                                                           

They can also prevent the water from washing the earth away. (4)We have come to realize that cutting down trees is harmful to human beings, animals and plants.                                                                                                                                                        

(5)We have built the Great Green Wall , but we still need

to work hard to protect the

environment.                                

8. What have you learned from this lesson?