Task 3 After reading the passage,discuss the following questions.

　　1.Why was the earth different from the other planets?

　　2.Why is it wrong to show films with dinosaurs and people together?

　　3.What problem is caused by human beings?

课堂提升

　　Summary

　　After the "Big Bang",the earth was still just a cloud of 　　　　.It 　　　　loudly with fire and rock,which were 　　　　 to produce 　　　　,nitrogen,water vapour and other gases.Then 　　　　 began to appear on its surface.

　　　　 which grew on the water are considered to be the earliest lives on the earth.The oxygen they supplied encouraged the lives of 　　　　.Slowly green plants grew on land,which were followed by 　　　　 like insects and 　　　　.When the plants grew into 　　　　,　　　　 appeared.Then 　　　　 developed but disappeared later,which made the rise of a totally different kind of animal,　　　　,possible,and finally 　　　　 spread all over the world.

　　Discussion

　　1.Do we human beings look after the earth well?What problems have been caused by human beings to the earth?

　　2.As a student,what little things can we do for the earth?Design an activity on Earth Day.

　　◆What the activity is about

　　◆Why the activity is designed

　　◆When and where to do the activity

　　◆Who takes part in the activity

　　◆What to be done in the activity

　　◆...

课后作业

　　1.Search the Internet for the information of the development of life.

　　2.Read the text again and find out your difficult points.

　　参考答案

　　课堂探究

　　1.Skimming

　　How life began on the earth.

　　2.Scanning

　　(1)Para.2　(2)Para.1　(3)Para.3　(4)Para.4　(5)Para.5

　　3.Intensive reading

Task 1