Step 3 Intensive reading (task 2)

　Read the whole text and finish the chart. (Pair work)

　Development of life

(Big Bang) The earth was still a cloud of dust. 　↓

(between 4.5 and 3.8 billion years ago) The dust settled into a solid globe. 　↓

(explode) Water vapor and some other gases were produced and made the earth`s atmosphere. 　↓

(cool down) Water appeared on the earth. 　↓

(life began) Arrival of small plants on the surface of the water. 　↓

(multiply) The oceans and seas were filled with oxygen and the development of shellfish and other fish were encouraged. 　↓

(next) Green plants began to grow on land. 　↓

(followed in time) Land animals such as insects and amphibians appeared. 　↓

(plants grew into forests) Reptiles appeared. 　↓

(after that) Huge animals, called dinosaurs developed. 　↓

(dinosaurs disappeared) It made the rise of mammals on the earth possible. 　

Step 4 Have a discussion (task 3)

Through the teacher`s description, we learned the development of life. It is a long and slow process. And the earth is the best place for all the living things to live on. But human beings didn`t take care of it.

Listen to the last paragraph twice with the books closed.

1). What problem is caused by human beings? (B)

A. They exist everywhere on the earth.

B. They caused global warming.

C. They find new methods of growing crops.

They enjoy hunting and fishing.