外研版高中英语选择性必修第二册精品课件 Unit 5 A delicate world Section A Starting out Understanding ideas.ppt

;Part1Readingcomprehension;;;Thenwhatiscausingtheincreaseintheglobalaveragesurfacetemperature?Climatescientistsoftenmentionakeyclimateprocesscalledthe“greenhouseeffect”,whichhastwocommonmeanings:the“natural”greenhouseeffectandthe“man-made”greenhouseeffect.The“natural”greenhouseeffectreferstothefactthatheatfromthesunenterstheatmosphereandwarmsEarth’ssurfaceasshort-waveradiation.Theheatisreleased2backintospaceatlongerwavelengths.Greenhousegasesintheatmosphere,suchasmethaneandcarbon3dioxide,trapsomeoftheheat,keepingEarth’sclimatewarmandhabitable.Withoutthisprocess,Earthcouldnotsustain4life.However,the“man-made”greenhouseeffecthasnowbecomeabigproblem.Whenpeopleproducehugeamountsofextragreenhousegasesbyburningfossilfuels5,moreheatenergyistrappedintheatmosphereandcausesEarth’ssurfacetemperaturetorisequickly.;Thereisstrongandcomprehensive6evidencethattheriseintemperaturehasledtoanincreaseinextremeweatherandnaturaldisastersworldwide,notonlycausingseriousdamage,butalsocostinghumanlives.Climatescientistshavewarnedthatifwedonottakeappropriateactions,thiswarmingtrend7willprobablycontinueandtherewillbeahigherpricetopay.Infact,newsreportsarefrequently8broadcast9aboutextremerainstormsandheatwavescausingdeathsandeconomiclosses.;【词汇积累】

1.ecologyn.生态;生态学

2.releasevt.n.排放;释放;发布

3.carbonn.碳

4.sustainvt.维持;遭受;承受住

5.fueln.燃料;刺激性言行

6.comprehensiveadj.全部的;所有的;详尽的

7.trendn.趋势;趋向;动向

8.frequentlyadv.频繁地;经常

9.broadcastvt.vi.播送;广播;传播;;第一步速读课文理清脉络

Activity1Whatdoesthetextmainlytellus?

A.ThehistoryofMacquarieIsland.

B.ThechaosofMacquarieIsland.

C.HowtoprotectMacquarieIsland.

D.HowMacquarieIslandwassavedfromdestruction.;Activity2Readthepassageandchoosethemainideaofeachpart.

1.Part1(Para.1)A.Theisland’smorerecenthistoryisatragicstory.