Whichpartoftheworldhasthemostnearsightedstudents？Justlookaroundyou-it'sEastAsia．Nineinten schoolleaversinmajorEastAsiancitiesarenearsighted，accordingtotheBBC．Expertssaybooksandvideogamesarenottoblame．EastAsianstudents，theysay，aren'tgettingenoughsunlight．
Peoplebecomenearsightedbecausetheireyeballsgrowoutofshapeandlightenteringtheireyescannotfocuscorrectly．Thebodycanproduceachemicalcalleddopamine （多巴胺） tostopeyeballsfromchangingshape．Andguesswhatscientistshavejustdiscovered？Sunlightcanhelpourbodiesproducemoredopamine，reportedAFP．
Accordingtothestudy，primaryschoolstudentsinSingaporespendonly30minutesoutdoorseveryday； inAustralia，bycontrast，kidsspendaboutthreehoursadayoutside．Asaresult，fewer children inAustralia are nearsighted-only10percent，comparedwith90percentinSingapore．
"ChildreninEastAsiabasicallygotoschool…gohomeandstayinside．Theystudyandtheywatchtelevision，"IanMorganoftheAustralianNationalUniversitytoldAFP．
Butbeingabookwormoracouchpotatodoesnotdirectlyharmtheeyes，addedMorgan．"Aslongastheygetoutside，itdoesn'tseemtomatterhowmuchstudytheydo，"heexplained．"Therearesomekidswhostudyhardandgetoutsideandplayhardandtheyaregenerallyfine．Theoneswhoareatmajorriskaretheoneswhostudyhardanddon'tgetoutside．Asaresult of massive （巨大的） educationalpressuresandtheconstruction （构成） ofachild'sday，theamountoftimetheyspendoutsideinbrightlightisminimized．"
Expertssuggestchildrenshouldstayoutsidefortwotothreehourseveryday．Thiscanincludetimespentintheplaygroundandwalkingtoandfromschool．
41．Whichofthefollowingwordhasthesimilarmeaningastheunderlinedphrase"nineinten"？___
A．many
B．much
C．more
D．most
42．WhatisthemainreasonforthelargenumberofnearsightedstudentsinEastAsia，accordingtoscientists？___
A．Toomuchreadingorgaming．
B．Lackofsunlight．
C．Geneticreasons．
D．Lackofexercise．
43．WhatcanweconcludefromParagraph2