In this study an extended Rouse formalism is used to obtain results belonging to (i) linear chains (K beads; K-1 Hookean springs), (ii) K x K cubic networks, or (iii) K x K x K cubes immersed in a Newtonian fluid. These three systems are subjected to small-amplitude oscillatory shear flow of frequency omega and the resulting dynamic moduli G＇(omega) and G "(omega) show significant differences. For large K, the corresponding relaxation spectra H(lambda) appear to be smooth functions of time lambda, in which some obvious discontinuities are observed, i.e., the so-called Van Hove singularities (well known in solid-state physics). Actually, for these three systems a relation is obtained between H(lambda) and the frequency spectra g(omega) used in solid-state physics.