人教2003课标版《Learning about Language》PPT课件优质课下载

人教2003课标版《Learning about Language》PPT课件优质课下载

The Evolution of Life on the Earth

Reviewing:

No one knows exactly how the earth began. According to a widely accepted theory, the earth began with a “Big Bang”, which exploded loudly and produced water vapour many gases, making the earth’s atmosphere. As the earth cooled down, water appeared and stayed on the surface. It was the presence of water that allowed the earth to dissolve harmful gases and acids into the oceans and seas, which made it possible for life to develop.

First, the appearance of small plants encouraged the development of early shellfish and all sorts of fish. Next, green plants began to grow on land. They were followed by land animals. So reptiles appeared for the first time. Later, dinosaurs developed. However, they suddenly disappeared. After that, mammals came into being. Finally, humans appeared and spread all over the earth. However, they are putting too much carbon dioxide into the atmosphere, making the earth too hot to live on. So whether life will continue on the earth will depend on whether this problem can be solved.

【自主学习】

Task I

Words：

1. 系统 n. _______

2. 氧 n. ___________

3. 猛烈的 adj. __________

4. 天文学 n. __________

5. 有害的 adj. ________

6. 存在 vi. ______________

7. 使困惑 vt. ______________

8. 太阳的 adj. _____________

system

oxygen

violent

astronomy

harmful

exist

puzzle

solar

Phrases：

9. 及时; 终于 __________