  We make comments on Kim and Chan's [{\it Phys. Rev. Lett.} 97, 115302 (2006)]
letter. Based on their pressure-dependent measurements (by a torsional
oscillator technique), we propose that the {\it supersolid} fraction
($\rho_s/\rho$) might be relevant to an sound absorption or attenuation
(fluctuations of pressure waves) in microscopic domain since there is no
apparent change in $T_c$ with pressure.
