  The nonet symmetry scheme seems to describe rather well the masses and
$\eta-\eta^{\prime}$ mixing angle of the ground state pseudo-scalar mesons. It
is expected that nonet symmetry should also be valid for the matrix elements of
the pseudo-scalar densitty operators which play an important role in charmless
two-body B decays with $\eta$ or $\eta^{\prime}$ in the final state. Starting
from the divergences of the SU(3) octet and singlet axial vector currents, we
show that nonet symmetry for the pseudo-scalar mass term implies nonet symmetry
for the pseudo-scalar density operators. In this nonet symmetry scheme, we find
that the branching ratio $B\to PP,PV$, with $\eta$ in the final state agrees
well with data, while those with $\eta'$ are underestimated, but by increasing
the $B\to \eta'$ form factor by $40-50%$, one could explain the tree-dominated
$B^{-}\to \pi^{-}\eta'$ and $B^{-}\to \rho^{-}\eta'$ measured branching ratios.
With this increased form factor and with only a moderate annihilation
contribution, we are able to obtain $62\times 10^{-6}$ for the
penguin-dominated $B^{-}\to K^{-}\eta'$ branching ratios, quite close to the
measured value. This supports the predicted value for the $B\to \eta'$ form
factor in PQCD and light-cone sum rules approach. A possible increase by 15% of
$<0|\bar{s} i\gamma_5 s|s\bar{s}>$ for $\eta_{0} $ would bring the predicted
$B^{-}\to K^{-}\eta'$ branching ratio to $69.375\times 10^{-6}$, very close to
experiment.
