  A clustering aspect is explained for the $^9$Be nucleus in charged-lepton
deep inelastic scattering. Nuclear modifications of the structure function
$F_2$ are studied by the ratio $R_{\rm EMC} = F_2^A /F_2^D$, where $A$ and $D$
are a nucleus and the deuteron, respectively. In a JLab experiment, an
unexpectedly large nuclear modification slope $|dR_{\rm EMC}/dx|$ was found for
$^9$Be, which could be related to its clustering structure. We investigated a
mean conventional part of a nuclear structure function $F_2^A$ by a convolution
description with nucleon momentum distributions calculated by antisymmetrized
(or fermionic) molecular dynamics (AMD) and also by a simple shell model. We
found that clustering effects are small in the conventional part, so that the
JLab result could be associated with an internal nucleon modification or a
short-range nuclear correlation which is caused by high densities due to
cluster formation.
