Whenwecanseewellwedonotthinkaboutoureyesoften:Itisonlywhenwecannotseeperfectlythatwecometoseehowimportantoureyesare.Peoplewhoarenearsighted（近视的）canonlyseethingsthatareveryclosetotheireyes

　　Whenwecanseewellwedonotthinkaboutoureyesoften:Itisonlywhenwecannotseeperfectlythatwecometoseehowimportantoureyesare.

　　Peoplewhoarenearsighted（近视的）canonlyseethingsthatareveryclosetotheireyes.Manypeoplewhodoalotofcloseworksuchaswritingandreadingbecomenearsighted.Thentheyhavetowearglassesinordertoseedistantthingsclearly.

　　Peoplewhoarefarsightedfacejusttheoppositeproblem.Theycanseethingsthatarefarawaybuttheyhavedifficultyreadingabookiftheydon'tholditatarm'slength.Iftheywanttodomuchreadingtheymustgetglassestoo.

　　Otherpeopledonotseeclearlybecausetheireyesarenotexactlytherightshape.Thistoocanbecorrectedbyglasses.Somepeople'seyesbecomecloudybecauseofcataracts(白内障).Longagothesepeopleoftenbecameblind.Nowhoweveritispossibletooperateonthecataractsandremovethem.

　　Whennightfallscolorsbecomefainter（更模糊）totheeyesandfinallydisappear.Afteryoureyeshavegrownusedtothedarkyoucanseebetterifyouusethesideofyoureyesratherthanthecenters.Sometimesafterdarkyouseeasmallthingtoonesideofyou.Itseemstodisappearifyouturnyourheadinitsdirection.Thisisbecausewhenyouturnyourheadyouarelookingatthethingtoodirectly.Menonguarddutysometimesthinktheyseesomethingmovingtoonesideofthem.Whentheyturntolookstraightatittheycannotseeitanymoreandtheybelievetheyweremistaken.Howeverthismistakehappensbecausethecenteroftheeyewhichisverysensitive(敏感的)indaylightisnotassensitiveasthesidesoftheeyeafterdark

　　【小题1】Accordingtothepassagea_______ismorelikelytobenearsighted.

　　A．guardB．doctorC．writerD．painter【小题2】Peoplewhoarefarsighted_______.A．cannotdoalotofcloseworkwithoutglassesB．canonlyseethingsthatareveryclosetotheireyesC．havethesameproblemasthenearsightedpeopleD．havedifficultyreadingabookiftheyholditatarm'slength【小题3】Toseeasmallthingatnightweneedtolook_______.A．withwideopeneyesB．withhalfshute