  We study DIS with a spin-1 hadron or a nucleus polarized in arbitrary
direction. The differential cross-section in this case will have an azimuthal
dependence. We derive the dependence by including contributions from twist-2-
and twist-3 QCD operators. The twist-3 contribution is computed at tree-level.
A spin-1 hadron or nucleus can have nonzero tensor polarization. We find that
all structure functions related to the tensor-polarization of the initial
hadron can be extracted by study the azimuthal dependence. A nonzero result of
the structure functions of a nucleus from experiment will indicate nontrivial
inner structure of the nucleus.
