  We obatin the ratio $F_i^A/F_i^{D}$(i=2,3, A=Be, C, Fe, Pb; D=Deuteron) in
the case of weak and electromagnetic nuclear structure functions. For this,
relativistic nuclear spectral function which incorporate the effects of Fermi
motion, binding and nucleon correlations is used. We also consider the pion and
rho meson cloud contributions and shadowing and antishadowing effects.
