Asthepopulationoftheplanetincreases，sodoesthenumberofhomes，businesses，parkinglots，schools，airportsandroadways．Allthesestructuresrequireelectricitytobelighted．Humansdemandtheselights．Theywanttheirhomesmorecomfortableandstreetssafe．Theproblemisthatresearchershavefoundthatallthislighthasanegativeeffectonhumansandwildlifeaswell，sopleasetakecare．

Lessthan10yearsagoIdrovetoalesspopulatedsectionofmytown，laydowninthemiddleoftheroadandwatchedanattractivemeteorshower（流星雨）．Theareawasshortofbuildingsandstreetlights．IfIdidthattoday，Iwouldn'tbeabletoseethemeteorshower，butIwouldbesurelyrunoverbyacar．

NowadaysscientistsarefindinglightpollutioncanbealmostasbadasCO2Pollution．Ifyouhaveevertakenaflightatnight，youmustremembertheviewofcoloredlightsallaround--it'sbeautifulbutwasteful．Howextensivethisphenomenonisaroundtheworld!

Additionally，electricityneedstobecreated，andtheprocessofcreatingthatelectricitywillcausepollutionbygivingoffgreenhousegases．Thisaffectstheairwebreatheandourqualityoflife．

Apartfromhumans，ithasbeenprovedthatwildlifeisalsosufferingfromlightpollution．Thousandsofbirdsdieeachyearwhentheycrashintohighlylitbuildings，astheyareconfusedwhichdirectiontheyshouldgoinbythelight．Ithasbeenlongknownthattinyseaturtlesbecomelostandfollowlightsontheshoreinsteadofheadingtowardsthesea．

Fortunately，lightpollutionisoneoftheeasiestsourcesofpollutionthatcanbecorrectedwithoutanegativeeffect．Weshouldnotonlypaymoreattentiontolightpollution，butalsoreducelightpollutionbyavoidingusingunnecessarylighting．

56．ThestorygiveninParagraph2isto___．

A．describethepastbeautyofthetown

B．showtheadvantageofasmallerpopulation

C．analyzethechangesoflightsintown

D．provethedisadvantageoflightpollution

57．Thebirdsandtinyseaturtlesdieorgetlost，because___．

A．theyareunabletoseeclearlyatnight

B．theireyesaredestroyedbyrightlight

C．electriclightspreventthemfromheading

D．thelightcreated