The ground state of the quasi-two-dimensional Bose liquid in a periodic one-body potential is examined. The energy shift and density variation due to the periodic potential are calculated with a procedure which combines the paired-phonon analysis and canonical transformations. The results of this calculation are compared to the recent calculation of these effects which employed a correlated wave function and a cumulant expansion. The results are the same to lowest order. The advantages and disadvantages of each technique are explored.