高中英语必修三第四单元课件讲课稿

1、Unit 4Unit 4 Astronomy: the science of the Astronomy: the science of the starsstars第一页，共30页。What are the names of the eight planets that circle our sun? What is their order from the sun?第二页，共30页。第三页，共30页。地球地球(dqi) _木星木星 _火星火星 _水星水星 _海王星海王星 _土星土星(txng) _天王星天王星 _金星金星 _EarthJupiterMarsMercuryNeptuneSat

2、urnUranusVenus第四页，共30页。1. How old is the universe?2. How old is the earth?3. Which were the first creature or plants on earth?4. Do you know what the order for the development of plants and animals is?Several billion years ago.Between 4.5 and 3.8 billion years ago.Very small air-breathing creatures.

3、Free Talk第五页，共30页。Ideas about how life began第六页，共30页。 reading readingHow Life Began on the EarthHow Life Began on the Earth第七页，共30页。Fast readingA brief introduction on how the universe developed and how life began on the earth.第八页，共30页。 Careful readingPara 1: Para 2:Para 3:Para 4: Para 5: A widely a

4、ccepted theory about the formation of the universe.The formation of the earth.The importance of water for life.The development of plants and animals on the earth.The arrival of humans and their impact on the earth.Read the passage carefully and analyse its structure.earth, atmosphere and waterlife d

5、evelopmenthuman beings第九页，共30页。1. What is the original earths atmosphere made up of? 2. Why did scientists believe water is fundamental to the development of life?3. How did water come into being on the earth?4. Which kind of life-being first appeared on the earth, plants or animals? Why?5. Why were

6、 mammals different from all life forms in the past?第十页，共30页。Carbon, nitrogen, water vapour, and other gases.2. Why did scientist believe water is fundamental to the development of life?Because water allowed the earth to dissolve harmful gases and acids into the oceans and seas to ensure a following

7、chain reaction, which made it possible for life to develop. What is the original earths atmosphere made up of?3. How did water come into being on the earth?The explosion of the earth produced water vapor, which turned into water when the earth cooled down.第十一页，共30页。4. Which kind of life-being first

8、appeared on the earth, plants or animals? Why?At first, small plants began to appear on the surface of the water, they produce oxygen, which encouraged the later development of early shellfish and all sorts of fish.5. Why were mammals different from all life forms in the past?They were different bec

9、ause they produced their young from within their bodies and produce milk to feed them.第十二页，共30页。 （ ）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 grow on dry land. （ ）7

10、 The earth was a cloud of dust. （ ）8 Water appeared on the earth. （ 9 Shellfish and other fish appeared. （ ）10 The universe began with a “Big Bang”. （ ）11 Clever animals with hands and feet appeared. （ ）12 Mammals appeared.875）64110392 Put the order of development of life. 12 11 第十三页，共30页。Let review

11、 the evolution of life on the earth.第十四页，共30页。After the “Big Bang”, the earth was full of water.第十五页，共30页。Original cells appeared in the ocean.第十六页，共30页。The cells in the water began to separate. Small plants came into being.第十七页，共30页。Early shellfish and all sorts of fish第十八页，共30页。Some animals (amphi

12、bian & insects) came to land.第十九页，共30页。Reptile appeared. 第二十页，共30页。dinosaurs 第二十一页，共30页。mammals第二十二页，共30页。Man had evolved from apes. 第二十三页，共30页。We are making the world better.We are making the world worse.Discussion第二十四页，共30页。 Because they are putting too much carbon dioxide into the atmosphere.

13、The earth may become too hot to live on .第二十五页，共30页。The earth is becoming hotter and hotter!第二十六页，共30页。 solar energy plant trees recycle rubbish prevent desertificationsave water purify airWhat can we do to take care of the earth?第二十七页，共30页。Whether life will continue on the earth depends on human beings.第二十八页，共30页。精讲点拨精讲点拨(din bo) The earth became so violent that it was not clear whether the shape would last or not. What many scientists believe is that the continued presence of water allowed the earth to dissolve harmful gases and