  Consequences of the interference between external and internal spectator
amplitudes for the lifetimes and semileptonic decay fractions of $B^0$ and
$B^+$ mesons are discussed. Extrapolating from the constructive interference
observed in 11 exclusive hadronic $B$ decays we find an inclusive semileptonic
decay fraction of $(11.2 \pm 0.5 \pm 1.7)$\%, significantly closer to the
experimental results than previous predictions.
