【正文】 atories. Student: 全國免費咨詢電話： 4000123267 Exactly. Anyway, ever sincethey started working on it,it’sbeen sonoisy wecan barely hear ourselvessing. Manager: Letalone sing. Student: Fetabout mean,wekeep the windowsdownand everything, but once thosebulldozersget going, I mean thosemachinesare loud. We’ve already had to cutshort two rehearsalsand we’ve got a concert in 6weeks. Manager: Well, that’snot good. I’m assuming you’vetried to rescheduleyour don’tdo construction work atnight. Student: I ran that by the group, but there werejusttoo many. I meanevenings arereally hard. It seemslike everyone inthe choir already has plans and someevenhave classes at night. Manager: And what about the musicbuilding? Student: You know, originally wewerebooked in one ofthe rehearsalroomsin the music building,but then weswitched withthe ’re a muchsmaller group and they saidthe acou stics,the sound inthat room, wasbetter forthem. So having usmoved to a bigger spacelikethe Lincoln Auditorium seemedlike a reasonableidea. Manager: 全國免費咨詢電話： 4000123267 Butnow... Student: Allthat don’tknow. Ijust wonderifthe jazzensembleknew what wasgoing to happen. Manager: Well, that wouldn’tbe very nice. Student: No. Butit reallywasquite a , now the musicbuilding’s fullybooked, mornings,afternoons, everything, wejust needa quiet it hasto have a piano. Manager: A piano. Ofcourse someof theother auditoriums have pianos, but that’s not going to beeasy. Student: You think they’re pretty booked up? Manager: Probably. Butit can’t hurt to check. What about Bradford Hall? I remembera piano in the oldstudent center there. Student: At thispoint, we’d be gratefulfor any quiet place. Manager: Can you... How flexiblecan you beon times? You said no evenings,but what ifI can’t findsomething open at 3 o’clock? Can you moveearlieror later? Student: 全國免費咨詢電話： 4000123267 I wish Icould say another timewould beokay, but you know how it is,everybody’salready got mitmentsfor the wholesemester2:30 or 3:30 would probably beokay, but I don’t think wecould go much outsidethat Manager: Well, check with metomorrow morning. I should’ve fo und something by then. It might not be ideal... Lecture1 Narrator: Listen to apart oflecturein a geology class Professor: Now there aresomepretty interesting cavesin parts ofthe westernUnitedStates, especialy innational parks. Thereisone part that has over a hundred caves, including someofthe largestonesin the ofthe moreinteresting onesis calledLechuguilla Cave. Lechuguilla hasbeen exploreda lot in ’sa pretty exciting placeI think. It wasmentionedonly briefly inyour books. So can anyone remember whatit said? Ellen? Male student: It’sthe deepest limestonecave in the ? Professor: That’sright. It’sone of thelongestand deepest limestonecaves not justin the country but inthe , whatelse? Male student: 全國免費咨詢電話： 4000123267 Well,it wasformed becauseofsulfuricacid, right? Professor: That’sit. Yeah, whathappens isyou have deepunderground oil depositsand there bacteria. Herelet medraw a diagram. Part ofthe limestonerock layer ispermeatedby water from curly lines are supposedto be cracks inthe rock. Below thewater tableand rock feed on thisoil and releasehydrogen sulfide ishydrogen sulfide,rises up and mixes with oxygen in theunderground water that sitsin the cracks and fissuresin when hydrogen sulfidereactswiththe oxygen in the water,the resultof that issulfuricacid, OK? Sulfuric acid eatsaway at limestone very you get bigger cracks and then passagewayis beingformedalong the openingsin the rock and it isallunderground. Ah yes, Paul? Male student: So that water? itisnot flowing,right? It’sstill? Professor: Yes,so thereare twokinds of limestone about 90percent ofthem, you have waterfrom the surface,streams,waterfall or whatever movingwater that flowsthrough cracks found in limestone. It’s themoving wateritself that wearsaway at the rock and ,in surfacewater,there isa weak acid, carbonic acid, not sulfuricacid but carbonic acid that helpsdissolvethe rock. Witha littlehelpfrom this carbonic acid, movingwater formsmostof theworld’s limestone 全國免費咨詢電話： 4000123267 caves. WhenI wasresearchingthis fora study a fewyears ago, I visiteda coupleof thesetypical limestonecaves,and theywereall very wet,you know, from streams and rivers. Thisflowing watercarved out the cavesand thestructures insidethem. Male stu