unit4天文学阅读详解.ppt

The main idea of the reading passage: The text mainly tells us the formation of the earth and the development of life on the earth. Para1 The formation of the universe How did the universe begin? According to a widely accepted theory, the universe began with a “Big Bang”. Big Bang ↓ stars ← → other bodies Para 2 The formation of the earth 1.The earth: a cloud of 2.Between 4.5 and 3.8 billion years ago, the dust settled into a solid . 3.After the earth exploded with fire and rock, they produced carbon dioxide, nitrogen, water , and other . Para3 The importance of water for life Why was water so important? Because water was ＿＿＿＿＿ to the development of life. And it allowed the earth to dissolve ＿＿＿ gases and acids into the oceans and seas. Para4 The development of plants and animals on the earth Extremely small ＿＿＿ on the surface of the water Early ＿＿＿ and all sorts of fish Green plants on land Some animals: land animals, insects, ＿＿＿＿＿, reptiles, huge animals (dinosaurs) and＿＿＿＿＿. Para5 the arrival of human beings and their effects on the earth About 2.6 million years ago, some ＿＿＿ animals (human beings) appeared, with hands and feet. Question1: What problems is caused by human beings? People are putting too much carbon dioxide into the atmosphere. Give the correct order of development of life 1. Insects and amphibians appeared. 3. The earth became a solid ball. 5. Reptiles appeared. 7. The earth was a cloud of dust. 9. Shellfish and other fish appeared. 11. Clever animals with hands and feet appeared. 2. Dinosaurs appeared. 4. Small plants grew on the water. 6. Plants began to grow on dry land. 8. Water appeared on the earth. 10. The universe began with a Big Bang. 12. Mammals appeared. Homework 1. Please find out some important expression