We report high-precision neutron scattering measurements of the temperature dependence of the phonon and roton excitations in liquid $^{4}\mathrm{He}$ at saturated vapor pressure in both the superfluid and normal-fluid phases. Two wave vectors were examined in detail: Q=0.4 A${\mathrm{\r{}}}^{\mathrm{\ensuremath{-}}1}$ in the phonon region and Q=1.925 A${\mathrm{\r{}}}^{\mathrm{\ensuremath{-}}1}$ at the roton minimum. The goal is to understand excitations in Bose liquids by determining the dynamic structure factor S(Q,\ensuremath{\omega}) accurately in both phases. At Q=0.4 A${\mathrm{\r{}}}^{\mathrm{\ensuremath{-}}1}$ the sharp peak in S(Q,\ensuremath{\omega}) broadens with temperature T, but remains sharp and well defined in the normal phase (Tg${\mathit{T}}_{\ensuremath{\lambda}}$) up to T\ensuremath{\approxeq}3 K. The rate of increase of the width of S(Q,\ensuremath{\omega}) shows a break at ${\mathit{T}}_{\ensuremath{\lambda}}$, but otherwise S(Q,\ensuremath{\omega}) is similar in the two phases and a transition could not be identified through S(Q,\ensuremath{\omega}). In contrast at Q=1.925 A${\mathrm{\r{}}}^{\mathrm{\ensuremath{-}}1}$, the sharp component of S(Q,\ensuremath{\omega}) disappears at ${\mathit{T}}_{\ensuremath{\lambda}}$ and S(Q,\ensuremath{\omega}) is very different above and below ${\mathit{T}}_{\ensuremath{\lambda}}$. This behavior is documented and values of the frequencies and linewidths at several temperatures are reported.