Unit4Globalwarming-It课件（新人教版选修6）.ppt

人教课标版 高二选修6 Unit 4;Discovering useful words and expressions (P28);1. Charles Keeling collected ______on the carbon dioxide content in the atmosphere over a forty-year period. He found that the amount of carbon dioxide _______ increasing during that time.;2. Although we are burning coal in huge _________ every year, we wont ________ of it for centuries. 3. If the amount of greenhouse gases continues to _______, we could be facing a global __________ .;4. Many scientists believe that global warming has __________ through the burning of fossil fuels. ;6. On the whole the warming of the earth is a ____________ that causes great concern. 7. The __________ shows temperature changes during the 20th century. 8. One hectare of forest can absorb 23 tons of carbon dioxide ____ year.;9. The washing machine uses too much energy, but _________ we buy a more economical one, it would still use too much water. 10. The car accident on the main road yesterday ___________ one driver’s death.;I. 代词 it a. 用作人称代词, 代替前文提到的事物。 My watch is missing. I can’t find (it) anywhere. Her father has gone abroad. Have you heard about (it)? ;b. 代替指示代词this, that。 What’s this? (It’s) a computer. Whose pen is that? It’s mine. c. 表示时间、天气、距离、季节等。 It’s time for lunch. It’s getting warmer and warmer．;II. 引导词： a. 作形式主语, 代替由不定式, 动名词或从句表示的真正主语。其基本句型为： It (形式主语) +adj. + to+ v. It (形式主语) +adj. + that (subject (主语)+v. ) ; It is +pp.+ that…=sb./sth. is to do ;① It is very important to help each other． ② It is no use / useless going there again． ③ It’s not decided yet when they will leave for Shanghai． ④ It seems that he has caught a cold. =He seems to have caught a cold．;b. 作形式宾语, 6123 结构 主语＋谓语＋it (形式宾语)＋宾语补足语＋to do sth. (doing sth. 或that从句).;① Marx found it important to study the situation in Russia. ② She thought it no use to write to him again. ③ They want to make it clear to the public that they do an important