  The $\eta$-meson photoproduction cross sections have been measured on the C
and Cu targets for the photon energies between 600 and 1100 MeV to investigate
the behavior of the $S_{11}$(1535) resonance in a nucleus. The excitation
functions of the cross section as well as the angular and momentum
distributions of $\eta$-mesons are in quantitative agreement with the Quantum
Molecular Dynamics (QMD) model calculations in which the $\eta$-meson emission
processes other than the $S_{11}$(1535) resonance are also incorporated as
proposed in the $\eta$-MAID model. It is shown that the excitation of the
$D_{15}$(1675) resonance might play an important role for $E_{\gamma}>900$ MeV.
