  The universe media is considered as a non-perfect fluid with bulk viscosity
and described by a more general equation of state. We assume the bulk viscosity
is a linear combination of the two terms: one is constant, and the other is
proportional to the scalar expansion $\theta=3\dot{a}/a$. The equation of state
is described as $p=(\gamma-1)\rho+p_0$, where $p_0$ is a parameter. This model
can be used to explain the dark energy dominated universe. Different choices of
the parameters may lead to three kinds of fates of the cosmological evolution:
no future singularity, big rip, or Type III singularity of Ref. [S. Nojiri,
S.D. Odintsov, and S. Tsujikawa, Phys. Rev. D \textbf{71}, 063004 (2005)].
