  Based on the factorization approach, we show that the CLEO data for the ratio
$\Gamma(B\to\psi K^*)/\Gamma(B\to \psi K)$ and the CDF measurement of the
fraction of longitudinal polarization in $B\to\psi K^*$ can be accounted for by
the heavy-flavor-symmetry approach for heavy-light form factors provided that
the form factor $F_0$ behaves as a constant, while the $q^2$ dependence is of
the monopole form for $F_1,~ A_0,~A_1$, and of the dipole behavior for $A_2$
and $V$. This $q^2$ extrapolation for form factors is further supported by
$B\to K^*\gamma$ data and by a recent QCD-sum-rule analysis. We then apply this
method to $B\to D(D^*)\pi(\rho)$ decays to extract the parameters $a_1$ and
$a_2$. It is found that $a_1(B\to D^{(*)}\pi(\rho))=1.01\pm 0.06$ and $a_2(B\to
D^{(*)}\pi(\rho))=0.23\pm 0.06\,$. Our result $a_2/a_1=0.22\pm 0.06$ thus
significantly improves the previous analysis that leads to $a_2/a_1=0.23\pm
0.11$. We argue that, contrary to what anticipated from the leading $1/N_c$
expansion, the sign of $a_2(B\to\psi\K)$ should be positive and
$a_2(B\to\psi\K)~{\large ^>_\sim}~ a_2(B\to D^{(*)}\pi(\rho))$.
