九上U2T2SC (2).ppt

Unit 2 Saving the EarthTopic 2 All these problems are very serious.In our daily life, we should face more environmental problems. Can you say something about them? cities, pollute, health problems factories, the land and the air, deadIn our daily life, we should face more environmental problems. Can you say something about them? cut down, millions of, take away the earth, become desertIn our daily life, we should face more environmental problems. Can you say something about them?fewer treesfactory pollutiontraffic pollutionthe ozone layermore carbon dioxideCan you match them? oxygen a special kind of oxygen called “ozone” (O3) a very big hole in the ozone layer, too much harmful radiation from the sunIn our daily life, we should face more environmental problems. CO2 carbon dioxide increase a lot, form a “blanket”, the heat from the sun cant escape cause the level of the sea to rise called “the greenhouse effect” or “globe warming”In our daily life, we should face more environmental problems. Watch and understand（视频（视频P37-1a）Can you choose a suitable title for each paragraph from the phrases below? The earth is 4 600 million years old. We humans have lived on earth for only 35 000 years, but during this period we have changed our planet a lot in many ways. Some things weve done are very good for the earth while some are bad._ All over the world, people have cut down millions of trees. When it rains or when the wind blows, the earth is taken away. Forests have become deserts, so more and more sorts of animals and plants are disappearing.Fewer Trees _ Carbon dioxide (CO2) in the air has increased a lot. It mainly comes from burning oil, coal and wood. This has formed a “blanket” around the earth. The heat from the sun cant escape so the temperature is rising. This is called “the greenhouse effect”. It causes the level of the oceans to rise and the climate of the earth to change. All these problems are very serious, so we must do something now.More Carbon Dioxide _ In big cities, cars and buses have polluted the air. Now many people in cities have health problems._Factories have also polluted the land and the water. As a result, many rivers and lakes are now dead._ Around the earth, theres a special kind of oxygen called “ozone”(O3). It is important to the earth. But now air pollution is destroying it and that has made a very big hole in the ozone layer. Too much harmful radiation from the sun passes through the hole and reaches the earth directly. This is very dangerous because this kind of radiation can cause cancer. Traffic PollutionFactory Pollution The Ozone Layer Ozone is very important to the earth.O3:Discuss the meanings of the following expressions and then write down how they affect the environment.A special kind of oxygen called “ozone”The ozone layer can prevent the suns harmful radiation from reaching the earth. But now air pollution is destroying the ozone layer. This is very dangerous because this kind of radiation can cause cancer. CO2:the greenhouse effect: More and more carbon dioxide forms a “blanket” around the earth.Written workDiscuss the meanings of the following expressions and then write down how they affect the environment.Carbon dioxide. It mainly comes from burning oil, coal and wood. Carbon dioxide around the earth makes the temperature rise. The heat from the sun cant escape so the temperature is rising. It causes the level of the oceans to rise and the climate of the earth to change.Read 1a again and choose the correct answers.1、What does our planet mean here? A. The sun. B. Mars. C. The moon. D. The earth.Read 1a again and choose the best answers.2、Which is NOT true? A. Cars can pollute the air. B. Factories can pollute the water. C. The fewer trees, the better. D. Not all the things we have done are good for the earth.3、The word it in the passage refers to _. A. CO2 B. O3 C. O2 D. H2ORead 1a again and choose the best answers.4、In the passage, “blanket” refers to _. A. carbon dioxide around the earth B. the ozone layer in the sky C. the forests around the world D. pollution all over the world5、The level of the oceans is rising because of _. A. pollution B. few trees C. the greenhouse effect D. changes in the climateRead 1a again and choose the best answers.6、What is the best title for this passage? A. Environmental Problems B. Pollution on the Earth C. Hope for the Future D. The Greenhouse EffectImportant sentences1.Some things weve done are very good for the earth while some are bad. while 表对比 “然而” I like English while he likes Chinese. 表并列 “ 当.时候” While we were talking, the teacher came in. = When the teacher came in, we were talking. 作名词用，表示“一会儿”“一段时间” She likes to lie down for a while after lunch. 4.Too much harmful radiation from the sun passes through the hole and reaches the earth directly.5.The heat from the sun cant escape so the temperature is rising.2.When it rains or when the wind blows,the earth is taken away.(被动语态 be +done) A lot of water can be saved by forests.3.As a result , many rivers and lakes are dead. be dead 死的 die v. 死 dead adj. 死的 death n. 死亡 dying adj. 快要死的 die-died -died-dying 6.It causes the level of the oceans to rise and the climate of the earth to change. cause sb./sth. to do sth. 导致某人/某物做某事 It can even cause them to become sick or deaf. ( )1.After the strong earthquake,_people were homeless. A.million B.millions of C.million of D.ten millions ( )2.-Whats the result of“the greenhouse effect”? -It causes the level of the sea A.rise B.raise C.to rise D.to raise ( )3.-Where does the carbon dioxide come from? -It comes from_oil,coal and wood. A.to born B.burned C.burn D.burning ( )4.Im watching TV _my sister is doing her homework. A.before B.after C.until D.while ( )5.-Remember this, children._careful you are,_mistakes you will make. We know,Miss Gao. A.The more;the fewer B.The more;the few C.The more;the less D.The more;the little people have cut down millions of trees. the earth is taken away.The heat from the sun cant escape so the temperature is rising.It causes the level of the oceans to rise