{{i}} quEstions 14 to 17 ArE BAsED on thE Following pAssAgE.At thE EnD oF thE pAssAgE, you will BE givEn 20 sEConDs to AnswEr thE quEstions. now, listEn to thE pAssAgE.{{/i}}

whAt is thE mAin topiC oF thE pAssAgEA．EnErgy ConsErvAtion.
B．trAnsportAtion oF thE FuturE.
C．strip CitiEs.
D．ADvAntAgEs oF Air trAnsportAtion ovEr rAilroADs.