【英语阅读理解2Forcenturiesmanhaddreamedofachievingverticalflight.In400A.D.Chinesechildrenplayedwithafan-liketoythatspunupwards,andfellbacktoearthasrotationceased.LeonardodaVinciconceivedthefirstmechanicalapparatu】
英语阅读理解2
Forcenturiesmanhaddreamedofachievingverticalflight.In400A.D.Chinesechildrenplayedwithafan-liketoythatspunupwards,andfellbacktoearthasrotationceased.LeonardodaVinciconceivedthefirstmechanicalapparatus,called“Helix”,whichcouldcarryamanstraightupbutthiswasonlyadesignandnevertested.
Theancientdreamwasfinallyrealizedin1940whenaRussianimmigrant,anaeronauticalengineer,pilotedastrange-lookingcraftofsteeltubewitharotatingfanontop.Itroseawkwardlyandverticallyintotheairfromastandingstart,hoveredafewfeetabovetheground,wentsidewaysandbackwards,andthensettledbacktoearth.Thatvehiclewascalledahelicopter.
Imaginationswerefired.Mendreamedofcommutingtoworkintheirpersonalhelicopter.Everymanwouldhaveoneinhisbackyard.Peopleanticipatedthatverticalflighttransportswouldcarrymillionsofpassengersastheairlinesoftodaydo.Suchfantasticexpectationswerenotfulfilled.
Thehelicopterhasnowbecomeanextremelyversatilemachine.Itexcelsinmilitarymissions,carryingtroops,gunsandstrategicinstrumentstoplaceswhereotheraircraftscannotgo.Corporationsusethemasairborneoffices.Manymetropolitanareasusetheminpolicework,constructionandloggingcompaniesemploytheminvariousadvantageousways,
engineersusethemforsite-selectionandsurveying,andoilcompaniesusethemasthebestwaytomakeoffshoreandremoteworkstationsaccessibletocrewsandsupplies.Anyurgent
missiontoahard-to-get-toplaceislikelyataskforahelicopter.Amongtheirothermultitudeofuses,theydeliverpeopleacrosstown,flytoandfromairports,assistinrescuework,and
aidinthesearchformissingorwantedpersons.
11.Whatisahelicopter?
A.Anaircraftthatcangofasterthantheordinaryairplane.
B.Anaircraftthatfitsintothesmallestpossibleplace.
C.Anaircraftthatcanflyupvertically
D.Anaircraftthatisusedonlyforcommercialservice.
12.Whatissaidaboutthedevelopmentofthehelicopter?
A.Helicoptershaveonlybeenworkedonbymansince1940.
B.AnEnglishmanwasthefirsttoachieveflightin