语篇理解 Thelastpartofthiscenturywillbeanageofexploration(探险)suchasmanhasneverknown.Thereare9planets,atleast30moons,andthousandsofasteroids(小行星).Theirtotalareaisabout250timesthatoftheearth.Spaceshipswillnotbeabletolandonsomeofthem.Butthatstillleavestobeexploredanarea10timesasgreatasthecontinentsoftheearth. Exploringspacemayseemterrifyingtosomepeople.Nodoubt(毫无疑问)explorersofthepastwereterrifiedbytheemptyoceansthatlaybeforethem.Theyconquered(征服)theirfears,crossedtheoceans,andbuilttheNewWorld. Inthepastwhenexplorerssetsailintotheunknown,theyhadtosaygood-byetoeverythingtheyknewathome.Spaceexplorerswillnotfacesuchgreatloneliness.Evenwhentheytravelfarbeyondthesun,theywillbeabletosendmessagesback.1.Accordingtothefirstparagraph,______.[ ]A.manhasnotknownhowtoexplorespaceyetB.spaceshipswillbeabletoreachsomeplacesinspaceC.anareatobeexploredifaslargeasthecontinentsoftheearthD.thetotalareatobeexploredifabout250timesthatoftheearth2.Futureexplorationwill______.[ ]A.bemoredifficultthanitwasinthepastB.coveralargerareathananyexploringdonebeforeC.bemoredangerousthaninthepastD.bemorelonelythaninthepast
3.Ifthelandareaoftheearthisabout55×106squaremiles,the
areathatcanbeexploredinspaceisprobably______squaremiles.
A.495×106 B.165×107
C.55×107 D.1375×1074.Nowspaceexplorerswillnotfeellonelybecause______.
A.theyaresoexcitedthattheyforgeteverythingathome
B.theyhavealreadysaidgood-byetoeverybodytheyknow
C.theyhavebeenabletoconquerfearsandlonelinessD.theykeepintouchwiththeearthatanytime5.Thewriterthinksthatalltheareasthatcanbeexploredaretobeexplored______.
A.attheendofthenineteenthcentury
B.attheendofthenextcentury
C.attheendofthetwentiethcenturyD.inthefar-distantfuture