This is the reason for why this statement is false: "iffirmsadjustedtheirpriceseveryday,thentheshort-runaggregate-supplycurvewouldbehorizontal":

Iffirmsadjustedpricesquicklyandifstickypricesweretheonlypossiblecauseforthe upwardslopeoftheshort-runaggregatesupplycurve,thentheshort-runaggregate-supplycurvewouldbevertical,nothorizontal.Theshort-runaggregatesupplycurvewouldbe horizontalonlyifpriceswerecompletelyfixed.

BUT I still cannot know understand the reason can someone further explain it in more details?