专题十六阅读理解之科普类阐明文

1.【·湖北卷】D

Theoddnessoflifeinspaceneverquitegoesaway.Herearesomeexamples.

Firstconsidersomethingassimpleassleep.Itspositionpresentsitsownchallenges.Themainquestioniswhetheryouwantyourarmsinsideoroutsidethesleepingbag.Ifyouleaveyourarmsout,theyfloatfreeinzerogravity,oftengivingasleepingastronautthelookofafunnyballed（芭蕾）dancer.“I’maninsideguy,”MikeHopkinssays,whoreturnedfromasix-monthtourontheInternationalSpaceStation.“Iliketobewrappedup.”

Onthestation,theordinarybecomesstrange.TheexercisebikefortheAmericanastronautshasnohandlebars.Italsohasnoseat.Withnogravity,it’sjustaseasytopedalviolently.Youcanwatchamoviewhileyoupedalbyfloatingamicrocomputeranywhereyouwant.Butstationresidentshavetobecarefulaboutstayinginoneplacetoolong.Withoutgravitytohelpcirculateair,thecarbondioxideyouexhale(呼气)hasatendencytoformaninvisible（隐形的）cloudaroundyouhead.Youcanendupwithwhatastronautscallacarbon-dioxideheadache.

LeroyChiao,54,anAmericanretiredastronautafterfourflights,describeswhathappensevenbeforeyoufloatoutofyourseat,”Yourinnerearthinksyour’refalling.Meanwhileyoureyesaretellingyouyou’restandingstraight.Thatcanbeannoying—that’swhysomepeoplefeelsick.”Withinacoupledays—trulyterribledaysforsome—astronauts’brainslearntoignorethepanickysignalsfromtheinnerear,andspacesicknessdisappears.

Spacetravelcanbesodelightfulbutatthesametimeinvisiblydangerous.Forinstance,astronautslosebonemass.That’swhyexerciseisconsideredsovitalthatNationalAeronauticsandSpaceAdministration(NASA)putsitrightontheworkdayschedule.Thefocusonfitnessisasmuchaboutscienceandthefutureasitisaboutkeepinganyindividualastronautsreturnhome,and,moreimportantly,howtomaintainstrengthandfitnessforthetwo