电子课件：人教新课标高中英语必修三Unit 4 Astronomy_ the science of the stars课件(4)

4. There used to be nine planets in the solar system. Recently scientists have decided that one of them can no longer be considered a planet. Do you know the name of that planet? Do you know why they removed it? Pluto. Scientists now think it is too small to be called a planet.
2. Why did the plants grow before the animals came? Because plants provide oxygen for animals to breathe.
3. Why is it wrong in films and stories to show dinosaurs and people together? Because dinosaurs died out long before human beings developed on the earth.
Unit 4 Astronomy: the science of the stars
Summary
How life began on the earth
“Big Bang”
stars
_a_t_o_m__s__
other bodies
Earth: a cloud of _d_u_s_t_
a solid _g_lo_b_e_ other 4.
early _s_h_e_l_lish
green plants on land
amphibians
land animals
insects
__r_e_p_t_il_e_s ___
huge animals (dinosaurs)
human beings
5. What problem is caused by human beings? Human beings caused global warming.
Read the passage again and underline all the discourse markers and sentence connectors.
Para. 4 Para. 5
The formation (形成) of the earth. The importance of water for life. A widely accepted theory about the formation of the universe. The arrival of humans and their impact on the earth. The development of plants and animals on the earth.
The order of development of life
The universe began with a “Big Bang”. The earth was a cloud of dust. The earth became a solid ball. Water appeared on the earth. Small plants grew on the water. Shellfish and other fish appeared.
the rise of _m__a_m__m_a_l_s_
Comprehending
Read the passage carefully and analyse its structure. Write the main idea for each paragraph.
Para. 1 Para. 2 Para. 3
How did the earth’s atmosphere develop? Why did water stay on the earth but not on the
other planets? How did life forms develop? Why did some life forms disappear?
Discourse markers: however, next, after that, later, finally, thus, as a result of this
Sentence connectors or conjunctions: and, but, because
The other puzzles hidden the passage are:
carbon nitrogen water vapour _g_a_se_s_
the earth’s _a_t_m__o_sp_h__er_e___
Water: f_u_n_d_a_m__e_n_t_a_l _ to the development of life
extremely small _p_la_n_t_s__ on the surface of the water
Plants began to grow on dry land. Insects and amphibians appeared. Reptiles appeared. Dinosaurs appeared. Mammals appeared. Clever animals with hands and feet appeared.
Think about what you have read and discuss these questions in pair.
1. Why was the earth different from other planets? The water remained on the earth.