问题详情

根据以下内容，回答下列各题。1．Whydoairplanestakelongertoflywestthaneast？Itcantakefivehourstogowest-eastfromNewYork(NY)toLondonbutsevenhourstotraveleast-westfromLondontoNY．Thereasonforthedifferenceisanatmosphericphenomenonknownasthejet(喷射)stream．ThejetstreamisaveryhighaltitudewindwhichalwaysblowsfromthewesttotheeastacrosstheAtlantic．Theplanesmovingataconstantairspeedthusgofasterinthewest-eastdirectionwhentheyaremovingwiththewindthanintheoppositedirection．2．WhatwouldhappenifthegravityonEarthwassuddenlyturnedoff？Supposingwecouldmagicallyturnoffgravity．Wouldbuildingsandotherstructures(建筑物)floataway？WhathappenedwoulddependonhowstronglythethingswereattachedtotheEarth．TheEarthismovingatquiteaspeed,movingatoverathousandmilesperhours．Ifyouturnsomethingaroundyourheadonastring(细绳),itgoesaroundinacircleuntilyouletgoofthestring．Thenitfliesoffinastraightline．Switchingoffgravitywouldbelikelettinggoofthestring．ThingsnotattachedtotheEarthwouldflyoffinastraightline．Peopleinbuildingswouldsuddenlyshootup-wardsatagreatspeeduntiltheyhittheceiling．Mostthingsoutsidewouldflyoffintospace．Whatinformationcanwegetfromthefirstpassage？
A.Itisthejetstreamthataffectshowfastairplanesfly
B.Planesgoslowerwhentheyaremovingwiththewind
C.IttakesmoretimetoflyfromNYtoLondonthanfromLondontoNY
D.ThejetstreamalwaysblowsfromtheeasttothewestacrosstheAtlantic
请帮忙给出正确答案和分析，谢谢！