  The effects of final-state interaction of hadrons, produced in $e^{+}e^{-}$
annihilation near the threshold, are discussed. If there is a loosely bound
state or a virtual state in a system of produced hadrons, then the energy
dependence of hadroproduction cross section is very strong. Our approach is
based on the use of the effective potentials accounting for the interaction
between hadrons in the final state. The cases of a few channels with nonzero
transition amplitudes between them are considered. It is shown that these
transitions drastically change the energy dependence of the cross sections. In
particular, a narrow resonance below the threshold in one channel leads to a
broad peak in another channel. We explained the non-trivial energy dependence
of the production cross sections of $B\bar{B}$, $B^{*}\bar{B}$, $B\bar{B}^{*}$,
$B^{*}\bar{B}^{*}$ near the thresholds in $e^{+}e^{-}$ annihilation and
obtained good agreement between our predictions and the experimental data
available.
