埃菲尔铁塔的整个塔体结构高耸，上窄下宽 ,给人以平衡稳定的美感。大到整个塔体、至塔柱不仅具有高扬的精神动势而且还要具备每一个部件在三维坐标系中均呈对称性。人教版必修人教版必修3 3Unit 4 Astronomy: the science of the starsHow Life Began on the EarthreadingPangu separates the sky from the earthThe Goddess Nuwa mended the heaven and created human beings from the clay(粘土粘土).God created the world in seven days Detailed reading This text can mainly divided into two stagesStage 1 : The development of the earthStage 2 : The development of life(para 13)(para 45)Stage 1: The development of the earth(1) After the Big Bang, what was the earth like? a cloud of dust a solid globe exploded with fire and rock produced water vapour and gases(2) What happened next?(3) What did the water vapour and gases form?the earths atmosphere Water appeared(4) What appeared as the earth cooled down?water is important for the beginning of life on the earth. Why is water so important for the beginning of life? Because water allowed the earth to dissolve harmful gases into oceans and seas.Stage2 The development of life small plants appears in water 1.What life developed after water appeared?Shellfish and all sorts of fish 2.What life developed in water next? green plants began to grow on land insects appeared3.What about the life on land?amphibians on land and in the waterforests4. What life developed next on land? reptiles appeared dinosaur developed 5.What life developed after forests appeared?mammals on land6.What life developed after dinosaurs? small clever animals7. What life developed after mammals? 1.Who are the small clever animals with hands and feet? 2. Are they taking care of the earth well? Why? Because they are putting too much carbon dioxide into the atmosphere, which prevents heat from escaping from the earth into space.The earth may become too hot to live on .Can you fill in the blanks?23456789101 small plants in watersellfish and all sorts of fish insects reptilesamphibiansmammalsdinosaurs humansplantsanimalsGreen plants on landforests1. Insects and amphibians appeared. 3. The earth became a solid ball.5. Reptiles appeared. 7. The earth was a cloud of dust9. Shellfish and other fish appeared.11. Clever animals with hands and feet appeared2. Dinosaurs appeared. 4.Small plants grew on the water.6. Plants began to grow on dry land.8. Water appeared on the earth10. The universe began with a “Big Band”.12. Mammals appeared.831091151741262Can you put the order of development of life into a time line?Group work : describe the videoThe earth is becoming hotter and hotterDiscussionWhat can we do to prevent the earth from becoming hotter and hotter? Eg. What we can do is to save energy. What we can do is tosummaryAfter the “big bang”, the earth was still just a cloud of _,it _loudly with fire and rock, which were _ to produce the_, water vapour and other gases. Then _ began to appeared on the earth. dustexplodedin timecarbonwater _ in water are considered to be the earliest lives on the earth. The O2they supplied encouraged the lives of_. Slowly green plants grew on land, which were followed by _like insects & _. When the plants grew into_, _ appeared. Then _ developed but disappeared later, which made the rise of a totally different animal,_, possible, and finally _ spread all over the world.shell-fish and fishamphibiansforestsreptilesdinosaursmammalhumansThe small plantsland animals 1. Finish the exercise 1and 2 on page 63 2. Read the text again and find out your difficult points.Homework:1. How was the earth different from the other planets?Comprehension questions2. What made it possible for life to begin to develop? Comprehension questions3. What are the differences between reptiles and mammals? Comprehension questions4. How did dinosaurs disappear? Comprehension questions