2019学年度人教版必修三Unit 4 Astronomy-The science of the starsPeriod1Reading

　Knowledge aims: get the students to earn the useful words and expressions: astronomy, system, religion, theory, atom, billion, globe, violent, carbon, atmosphere, unlike, fundamental, harmful, acid, chain, multiply, oxygen, exist, thus, dioxide, puzzle, solar system, in time, lay eggs, give birth to, in one`s turn, carbon dioxide, prevent...from.

　Skill aims: Improve students` reading comprehensive ability and enable them to know about how the earth came into being and the development of life.

　Teaching important and difficult points: discuss the development of life. What will our future be like if the earth becomes too hot to live? And what can we do to prevent such serious situation from happening?

　Step 1 Lead-in (Individual work)

　Lead in the passage by asking some questions:

　Did human beings live on the earth when the earth came into being?

( monkeys, Apes类人猿, gorillas猩猩, chimpanzees黑猩猩, primate灵长目动物)

　Do you know what plays the most important part in our body, water or fat?

　Do you know how did water come into being on the earth?

　Step 2 Fast reading (task 1)

　1. Read paragraph 1-3. After having read, let them watch the video of "Big Bang", and answer the question "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.)

　2. Careful reading: read the passage carefully and answer the following questions:

　1). What is the earth`s atmosphere made up of?

　(Carbon, nitrogen, water vapor and other gases)

　2). Why was the earth different from other planets? (B)

　A. It produced a lot of heat. B. The water remained.

　C. Water disappeared. D. It was the oldest planet.

　3). Why was water very important for the beginning of life?

　(Water allowed the earth to dissolved harmful gases and acids into the oceans and seas.)

3. Do the exercises and then check with the whole class.