  We discuss some differences and similarities between electron and neutrino
scattering off atomic nuclei. We find that, in the giant resonance region, the
two processes excite different nuclear modes, therefore the weak and the
electromagnetic nuclear responses are rather different. In any case, the
scattering of electrons and photons is the best guide we have to test the
validity of our nuclear models and their prediction power. The experience in
describing electromagnetic excitations of the nucleus, suggests that, when the
nucleus is excited in the continuum, the re-interaction between the emitted
nucleon and the remaining nucleus should not be neglected. A simple model
taking into account this final state interaction is proposed, and applied to
the neutrino scattering off 16O nucleus.
