Unit5Thepowerofnature教材背景链接基拉韦厄火山是世界上最大的活火山体，位于美国夏威夷岛东南部。这座活动力旺盛的活火山，至今仍经常喷发。MountKilaueaMountKilauea，theworld’smostactivevolcano，isontheislandofHawaii.ItisnotfarfromMaunaLoa，thelargestvolcanointheworld.MaunaLoaandMountKilaueatogetherformthevolcanoesNationalParkinHawaii.MountKilaueahasproducedlavamorethanfiftytimesinthelastonehundredyears.Sometimesthelavamovesslowly.Atothertimesitpoursoutveryfastasahugeamountofpressureforcesitfromthevolcano.Duringthesetimes，itmovesalmostasquicklyaswatermovingdownthesideofamountain.SometimesMountKilaueaproducesalargeamountoflavathatseemslikeriversoffire.WhenthelavafromMountKilaueareachestheocean，itsfierceheatproducesagreatamountofsteamthatrisesintotheair.Thelavaissohotthatitcontinuestoburnunderwaterforsometime.ThelavafromMountKilaueacontinuestoaddlandtotheislandasthevolcanoesofHawaiihavealwaysdone.ItwasthesevolcanoesthatformedtheislandsofHawaii.MostofthetimethelavaofMountKilaueaseemstomovepeacefullytowardtheocean.Yetitisnotaspeacefulasitseemsfromadistance.Inrecentyearsthelavadestroyedonesmalltownontheisland.Theboilingrockslowlycoveredthetown.Itblockedroadsanddestroyedthem.NothingcanstopthelavaofMountKilauea.ExpertssaythevolcanoesofMaunaLoaandMountKilaueaareaseriousthreattoproperty(财产)onmanypartsoftheisland.TheyalsosaythevolcanoesoftheislandofHawaiiareproofthatthechangingenvironmentoftheearthisandwillalwaysremainbeyondhumancontrol.新课导入新课导入只要我们——人类有时刻不忘保护环境的意识，有依法治理环境的意识，地球村将成为美好的乐园。未来的天空一定是碧蓝的，水是清澈的，绿树成荫鲜花遍地，人类可以尽情享受大自然赋予我们的幸福。虽然我们现在做的只不过是一些微小的事，但是我们坚信只要人人都有保护环境的责任心，从自己做起，从小事做起，携手保护我们的家园——大自然会给人类应有的回报。在温暖的摇篮——草地上小憩；在慈祥的笑脸——天空下成长；在爱的源泉——河流中沐浴。
