  The paper is concerned with conditions for the existence of almost periodic
solutions of the following abstract functional differential equation $ \dot
u(t) = Au(t) + [{\cal B}u](t) +f(t), $ where $A$ is a closed operator in a
Banach space $\X$, $\cal B$ is a general bounded linear operator in the
function space of all $\X$-valued bounded and uniformly continuous functions
that satisfies a so-called {\it autonomous} condition. We develop a general
procedure to carry out the decomposition that does not need the well-posedness
of the equations. The obtained conditions are of Massera type, which are stated
in terms of spectral conditions of the operator ${\cal A}+{\cal B}$ and the
spectrum of $f$. Moreover, we give conditions for the equation not to have
quasi-periodic solutions with different structures of spectrum. The obtained
results extend previous ones.
