AccordingtoNielsen,theaveragenumberofmobilephonecalls...
問題詳情： AccordingtoNielsen,theaveragenumberofmobilephonecallswemakeisdroppingeveryyear,afterhittingapeakin2007.Andourcallsaregettingshorter:In2005theyaveragedthreeminutesinlength;nowthey’realmost...