  We consider a simplified model for resonant neutron-nucleus interaction with
coupled channels. An analytical solution is given for two coupled channels and
arbitrary neutron orbital momentum. A case of a week channel coupling,
corresponding to narrow Breit-Wigner resonance, is analyzed in details. As far
as the total width of a resonance coincides with the neutron width, the model
is directly appropriate only for light nuclei. We study a mixing of two narrow
s- and p-wave resonances by P- and P-,T-noninvariant potentials in the first
order of perturbation theory. As an example a close-lying pair of s- and p-wave
resonances of the $^{35}$Cl nucleus is considered. The favorable possibilities
are shown to exist on thick targets for measurements beyond the resonance
widths. In particular, an interference minimum near s-wave resonance is of
interest for P-odd neutron spin rotation on light spinless nuclei.
