Inthelatel960s．manypeopleinNorthAmericaturnedtheirattentiontoenvironmentalproblems，andnewsteel-and-glassskyscraper,5werewidelycriticized．Ecologistspointedoutthataclusteroftallbuildingsinacityoftenoverburdenspublictransportationandparkinglotcapacities． Skyscrapersarealsolavishconsumers，andwasters，ofelectricpower．Inonerecentyear．Theadditionofl7millionsquarefeetofskyscraperomcespaceinNewYorkCityraisedthepeakdaibdemandforelectricitybyl20，000kilowatts--enoughtOsupplytheentirecityofAlbany，NewYork，foraday． Glass·walledskyscraperscanbeespeciallywasteful．Theheatloss(orgain)throughawallofhalf-inchplateglassismorethantentimesthatthroughatypicalmasonrywallfilledwithinsula．tionboard．Tolessenthestrainonheatingandairconditioningequipment，buildersofskyscrapershavebeguntousedoubleglazedpanelsofglass，andreflectiveglassescoatedwithsiNerorgold mirrorfilmsthatreduceglareaSwellasheatgain．However，mirror-walledskyscrapersraisethetemperatureofthesurroundingairandaffectneighboringbuildings． Skyscrapersputaseverestrainonacity’Ssanitationfacilities，t00．Iffullyoccupied，thetwoWorldTradeCentertowersinNewYorkCitywouldalonegenerate2．25milliongallonsofrawsewageeachyear--asmuchasacitythesizeofStamford,Connecticut,whichhasapopulationofmorethan109,000． Skyscrapersalsointerferewithtelevisionreception,blockbirdflyways,andobstructairtraffic． InBostoninthelate1960s,somepeopleevenfearedthatshadowsfromskyscraperswouldkillthegrassonBostonCommon． Still,peoplecontinuetobuildskyscrapersforallthereasonsthattheyhavealwaysbuiltthem-personalambition,civicpride,andthedesireofownerstohavethelargestpossibleamountofrentablespace． Themainpurposeofthepassageisto()
A.discuss the advantages and disadvantages of skyscrapers B.compare skyscrapers with other modern structures C.describe skyscrapers and their effect on the environment D.illustrate various architectural正确答案C
