Nuclearpower’sdangertohealthsafetyandevenlifeitselfcanbesummedupinoneword:radiation.Nuclearradiationhasacertainmysteryaboutitpartlybecauseitcannotbedetectedbyhumansenses.Itcan’tbeseenorheardort

　　Nuclearpower’sdangertohealthsafetyandevenlifeitselfcanbesummedupinoneword:radiation.

　　Nuclearradiationhasacertainmysteryaboutitpartlybecauseitcannotbedetectedbyhumansenses.Itcan’tbeseenorheardortouchedortastedeventhoughitmaybeallaroundus.Thereareotherthingslikethat.Forexampleradiowavesareallaroundusbutwecan’tdetectthemsensethemwithoutaradioreceiver.Similarlywecan’tsenseradioactivitywithoutaradiationdetector.Butunlikecommonradiowavesnuclearradiationisnotharmlesstohumanbeingsandotherlivingthings.

　　Atveryhighlevelsradiationcankillananimalorhumanbeingimmediatelybykillingmassesofcellsinvitalorgans.Buteventhelowestlevelscandoseriousdamage.Thereisnolevelsofradiationthatiscompletelysafe.Iftheradiationdoesnothitanythingimportantthedamagemaynotbeserious.Thisisthecasewhenonlyafewcellsarehitandiftheyarekilledimmediately.Yourbodywillreplacethedeadcellswithhealthyones.Butifthefewcellsareonlydamagedandiftheyreproducethemselvesyoumaybeintrouble.Theycangrowintocancer.Sometimesthisdoesnotshowupformanyyears.

　　Thisisanotherreasonforsomeofthemysteryaboutnuclearradiation.Seriousdamagecanbedonewithoutthevictimbeingawareatthetimethatdamagehasoccurred.Apersoncanbeirradiated（辐射）andfeelfinethendieforcancerfivetenortwentyyearslaterasaresult.Orachildcanbebornweakasaresultofradiationabsorbedbyitsgrandparents.

　　Radiationcanhurtus.Wemustknowthetruth.

　　【小题1】Whichofthefollowingstatementsistrue?

　　A．Nuclearradiationisjustlikecommonradiowaves. B．Nuclearradiationcancausecancertohumanbeings. C．Nuclearradiationcanbedetectedbyhumansenses. D．Nuclearradiationcanbesafetohumanbeingsifitslevelislow. 【小题2】Howcannuclearradiationkillananimal? A．Bydamagingitsheart. B．Bykillingafewcells. C．Byhittinganyplaceinitsbody. D．Bykillingmanycellsinimportantorgans.