listEning 8 "EnvironmEntAl sCiEnCEClAss" {$mEDiAurl} why DoEs thE proFEssor sAy this: A、to inDiCAtE thAt thE DAtE is not importAnt B、to proviDE A spECiFiC DAtE For thE ContrACt C、to CorrECt A prEvious stAtEmEnt ABout thE DAtE D、to show thAt hE is unCErtAin ABout thE DAtE