人教版B3 U4Warming up and reading56张.ppt

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. match the main idea with each paragraph. Para. 1 A.The formation(形成) of the earth. Para. 2 B.The importance of water for life. Para. 3 C.A widely accepted theory –the Big Bang Para. 4 D.The arrival of humans and their impact(影响) on the earth. Para. 5 E.The development of plants and animals on the earth. Water is fundamental to thedevelopment of life. Green plants grew into forests 4. What problem is caused by human beings? Human beings caused global warming. 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……) all sorts of fish green plants on land insects on land amphibians on land and in the water reptiles on land dinosaurs on land After that mammals on land small clever animals （ ）1 Insects and amphibians appeared. （ ）2 Dinosaurs appeared. （ ）3 The earth became a solid ball. （ ）4 Small plants grew on the water. （ ）5 Reptiles appeared. （ ）6 Plants began to g