  The neutrino-nucleon --> lepton pion QE reaction on the A-target is used as a
signal event or/and to reconstruct the neutrino energy, using two-body
kinematics. Competition of another processes could lead to misidentification of
the arriving neutrinos, being important the fake events coming from the
CC1-pion background. A precise knowledge of cross sections is a prerequisite in
order to make simulations in event generators to substract the fake ones from
the QE countings, and in this contribution we analyze the different nuclear
effects on the CC1-pion channel. Our calculations also can be extended for the
NC case.
