ResearchersatStanforduniversityhavedevelopedanewmaterialthatcanmoveheatoutofbuildingsandintospace.Theresearcherssaythematerialcancoolbuildingsevenonhotdays.Thecoolingmaterialisaverythinsheetwithmanyla

　　Researchersat Stanforduniversityhavedevelopedanewmaterialthatcanmoveheatoutofbuildingsandintospace. Theresearcherssaythematerialcancoolbuildingsevenonhotdays.Thecoolingmaterialisaverythinsheetwithmanylayersthatcouldbeplacedonarooflikesolarpanels(板)，However insteadofturningsunlightintoenergyassolarpanelsdothematerialturnsheatintoradiation.

　　ShanhuiFanisanelectricalengineeringprofessoratStanfordUniversity. Hesaysthatthepan-elshavealayerofmaterialthatislikesand. Thepanelsactlikeamirror. Theytakeheatoutofbuildingsandreflectthelightfromthesun. Andhesaysboththeheatandsunlightaresent100kilometersintoouterspace."It'sastructure(构造)thatcoolsitselfwithoutelectricityinputevenunderthesun. So whatitdoesisbasicallyradiateheattoouterspaceandalsoreflectthesunlightsoitdoesn'tgetheatedupbythesun. Mr.Fansaysitislikehavingawindowintospace.Theheatissentdirectlyintospacewithoutwarmingtheair.”

　　Hesaysbuildingsindevelopingcountriesthatdonothaveelectricityorairconditioningcouldusethepanels. "Inareaswhereelectricityisnotaccessible thereisasignificantpotentialbenefitforstoringmedicineorevenfood. Inmanyofthesesituationsbeingabletoreducethetemperatureisimportant. Andthiswouldprovideawaytodoit.”

　　Theresearcherssaythemainproblemiscreatingactualcoolingsystemsusingthehigh-techpanels. Theysayitmaybepossibletodevelopacoolingspray(喷涂)thatcouldbeusedonexist-ingsolidstructures. Theybelievethecoolingspraytechnologycouldbedevelopedinthenextthreetofiveyears. Theysayasmuchas15percentoftheenergyusedintheUnitedStatesisspentprovi-

　　dingpowertoairconditioningsystems.

　　68. Thefirstparagraphmainlytellsus .

　　A.Anewmaterialiscreatedtocoolthebuildings

　　B.Livingonhotdaysisnolongerabigproblemnow

　　C.Researchersaredevelopingnewsolarpanelsonroofs

　　D.Thenewmaterialisaverythinsheetwithmanylayers

　　69. Howdoesthepanelwork?

　　A.Itabsorbstheheatandcoolsitdown.

　　B.Itusesamirrortoreflectthesunlight.

　　C.Itha