Whenwethinkofgreenbuildingswetendtothinkofnewones-thekindofmodernsolar-paneledmasterpiecesthatmakethecoversofarchitecturemagazines．ButtheUShasmorethan100millionexistinghomesanditwouldbeincredibly totearthemalldownand themwithgreenerversions．

Anenormousamountofenergyandresourceswentintotheconstructionofthosehouses．Anditwouldtakeanaverageof65yearsforthe carbonemissions(排放)froma(an)__ _energy-efficient(节能)hometomakeupforthe lostbydestroyinganoldone．

Sointhebroadestsensethegreenesthomeistheonethathasalreadybeenbuilt．Butatthesametime halfofUScarbonemissionscomefromheatingcoolingandpoweringour officesandotherbuildings．"Youcan'tdealwithclimate withoutdealingwithexistingbuildings"saysRichardMoethepresidentoftheNationalTrust．

Withsomeexceptionstheoldesthomestendtobethe energy-efficient．Housesbuiltbefore1939useabout50%moreenergypersquarefootthanthosebuiltafter2000mainlyduetothetinycracksandgapsthat overtimeandletinmoreoutside .

thereareavastnumberofrelativelysimplechangesthatcangreenolderhomesfrom oneslikeLincoln'sCottagetoyourownpostwarhome．Andefficiencyupgrades(升级)cansavemorethanjusttheearth;theycanhelp propertyownersfromrisingpower .

小题1:A．terribleB．wastefulC．wonderfulD．useful小题2:A．putB．buildC．replaceD．take小题3:A．reducedB．increasedC．usedD．destroyed小题4:A．oldB．fashionableC．newD．beautiful小题5:A．magazinesB．treesC．materialsD．resour