  Neutrino scattering physics is discussed for investigating internal structure
of the nucleon and nuclei at future neutrino facilities. We explain structure
functions in neutrino scattering. In particular, there are new polarized
functions g_3, g_4, and g_5, and they should provide us important information
for determining internal nucleon spin structure. Next, nuclear structure
functions are discussed. From F_3 structure function measurements,
valence-quark shadowing should be clarified. Nuclear effects on the NuTeV
sin^2\theta_W anomaly are explained. We also comment on low-energy neutrino
scattering, which is relevant to current long-baseline neutrino oscillation
experiments.
