Unit5Thepowerofnature話題導(dǎo)入教學(xué)

Unit5Thepowerofnature話題導(dǎo)入你知道什么是龍卷風(fēng)，什么是颶風(fēng)嗎？你知道它們的威力有多大嗎？TheviolenceofnatureWhatisatornado?Atornadoisarotating(旋轉(zhuǎn)的)columnofairfromathunderstormtotheground.Themostviolenthavewindsofmorethan400kilometresperhour.AlmostallofthemoccurintheUS，intheareafromTexasinthesoutheasttoSouthDakotainthenorth.Tornadoescanpickupcars，trainsandevenhousesandputthemdowninthenextstreet—oreveninthenexttown.Theycantakethefuroffthebackofacatandthefeathersoffachicken.Theycandestroyhouses，butleavethefurnitureinsideexactlywhereitwas.Onaverage，thereare800tornadoesintheUSeachyear，causingabout80deathsandover1,500injuries.Theworsttornadoofalltimeoccurredin1925，affectingthreeUSstates：Missouri，IllinoisandIndiana.Bythetimeitended，about700peoplehadbeenkilledandmorethan2,000hadbeeninjured.Whatisahurricane?Hurricanesarestrongtropical(熱帶的)storms，andtheyusuallyoccurinthesouthernAtlanticOcean，theCaribbeanSeaandtheGulfofMexico.Thereareviolentwindsof120kilometresperhourormore，whichcausehugewaves，heavyrainandfloods.ThereareonaveragesixAtlantichurricaneseachyearandtheyusuallyaffecttheeastcoastoftheUSfromTexastoMaine.Theworsthurricanedisasterofalltimeoccurredonthe8thSeptember1900inGalveston，Texas.Windsofabout200kilometresperhourandfive-metrehighwaveshitthecity.Thedisasterkilled6,000peopleinapopulationof37,000anddestroyed3,600buildings.AnextraordinaryeventThisisastoryaboutthe1900Galvestonhurricane.CharlesCoghlanwasanineteenth-centuryIrishactorwhowenttoliveinCanada.HethenmovedtoNewYork，wherehebecamefamous.Bythelate1890s，hehadmovedtoGalveston，wherehediedin1899，ayearbeforethehurricanestruck.ThecemeterywhereCoghlanwasburiedwasdestroyedbythehurricaneandCoghlan’scoffinendedupinthesea.Eightyearslater，thecoffinwasfoundbyfishermenintheseaonPrinceEdwardIslandintheeastofCanada.TheGulfStreamhadcarriedit3,000kilometresuptheeasternUScoasttoPrinceEdwardIsland.CoghlantravelledbacktoCanada—afterhehadbeenburiedinTexas!True(T)orFalse(F)1．Thewindspeedofthemostviolenttornadoesisslowerthanthatofthemostviolenthurricanes.(

)【答案】F2．Hurricanescancausehugewaves，heavyrainandfloods.(

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