the science of the stars Unit 4 Astronomy: the science of the stars

冥王星 土星 海王星 木星 天王星 金星 地球 The Solar system 水星 火星

How life began on the earth? Big Bang Big Bang

Task 1: Skimming 1. Read the text quickly and match each paragraph with its main idea. Paragraph 1 A. The formation of the earth. Paragraph 2 B. The importance of water for life. Paragraph 3 C. The arrival of human beings and their effect on the earth. Paragraph 4 D. A widely accepted theory about the formation of the universe. Paragraph 5 E. The development of plants and animals on the earth.

2. According to the exercise above, try to write down the main idea of the text. The text mainly tells us____________ _________________________________. how the earth formed and how life began on the earth

Task 2: Scanning A B Scan the text and then choose the best answer 1. What began to appear on the earth’ s surface when it cooled down?_____ A. Water B. Gases C. Acids D. Carbon 2. How did the atmosphere on the earth appear?____ A. It came from space B. It came from the explosion C. It came from the oceans D. It came from the forests A B

A C D 3. Why did plants appear earlier than animals?_______ A. Because plants could produce oxygen, which was important for animals; B. Because plants were more advantage than animals; C. Because animals needed more water; D. Because plants needed more water; 4. From the last paragraph we can infer that the author is _________about the future of life on the earth. Confident B. sad C. concerned D. angry 5. According to the text we can know________. Only the earth has life on it in space; Oxygen in the atmosphere on the earth came from the Big Bang; Humans are the cleverest animals of the earth; Plants played an important part in the appearance of animals; C D

Task 3: Careful reading How life began on earth Fill in the blanks with key words according to what you have read from each paragraph. How life began on earth The universe began with a “_________” . Atoms formed and combined to create __________________. Big Bang stars and other bodies ↓

For several billion years after the big bang, the earth was still a______________. Between 4.5 and 3.8 billion years ago, the dust settled into a _________ . The earth _________to produce carbon, nitrogen, water vapour and other gases; The gases made the earth’s __________ ; As the earth cooled down, _______appeared on the earth ; ↓ The continued presence of water ________harmful gases and acids; Life began to develop ↓ cloud of dust solid globe exploded atmosphere water dissolved

a chain reaction ↓ plants animals human beings The first ________________in water filled water with________ The early_________________ developed Next _________________grew on land Land animals(_____,________) Followed. Later the plants grew into_____ ______, dinosaurs and_______ appeared. small plants shellfish and fish oxygen green plants insects amphibians forests Reptiles mammals ↓ human beings About 2.6 million years ago, ______________________________ appeared and spread all over the earth a chain reaction

2. Think about the following questions and discuss in group. ①The text is developed in the order of _____. The italicized(斜体字) words above help the author describe the complex process of the evolution of life on the earth clear. Can you find more in the text? plants animals The first small plants in water filled water with oxygen The early shellfish and fish Developed. Next green plants grew on land Land animals (insect, amphibians) Followed. Later the plants grew into forests Reptiles, dinosaurs and mammals Appeared. time For several billion years after the “Big Bang”, between 4.5 and 3.8 billion years ago, many millions of years later, for more than 140 million years,65 million years ago, about 2.6 million years ago, now. but, first, next, later, after that, thus, but, so.

② What problem did human beings cause on earth? ③What should we do to make life continue to survive on the earth? They are not looking after the earth very well. protect the environment, plant more trees, put less carbon dioxide into the atmosphere, …

Task 4: Homework Discuss in groups and give a report to the class. How life began on earth is one of the biggest puzzles that scientists found hard to solve. What other puzzles are hidden in the passage? Find them out and do some research.

Thank you!