人教版B3 U4Warming up and reading精品课件56张.ppt

2. What’s the correct way to prove a scientific idea? We should design experiments to test it for several times. Then we can analyze the results and draw a conclusion at last. 3. What are the most important skills we need to be real scientists? Careful, objective and logical, draw conclusions from the experiments and not impose conclusions on the data. (impose … on … 把……强加于……) Pre-reading 1. The origin of life on earth is a question that interests astronomers. What do you know about it? 2. Each religion and culture has its own ideas about how life began on earth. What do you know? In China, we all know that Pangu separates the sky from the earth and Nvwa made humans. 2. What form was the earth after the “Big Bang”? The earth was still just a cloud of dust. 3. What made up the earth’s atmosphere after the earth exploded? Carbon, nitrogen, water vapour and other gases. Careful reading I. Read the passage carefully and match the main idea with each paragraph. 5. What problem is caused by human beings? Human beings caused global warming. Summary 地球大气 1. When did the “Big Bang” happen? It happened several billion years ago. Scanning Read the passage quickly and answer the questions. 4. How did water come into being on the earth? As the earth cooled down after it exploded, water came into being. 5. What’s the significance of the presence of water on the earth? It allowed the earth to dissolve harmful gases and acids into the oceans and seas. 6. What was important to the development of fish? oxygen. 7. What made possible the rise of mammals on the earth? The disappearance of dinosaurs made the possible the rise of mammals on the earth. 8. Why are mammals different from all life forms in the past? They gave birth to young baby animals and produced milk to feed them. Para. 1 The formation (形成) of the earth. Para. 2 The importance of water for