  We examine the nuclear transparency for the quasi-elastic ($e, e'p$) process
at large momentum transfers in a relativistic quantum-mechanical model for the
internal structure of the proton, using a relativistic harmonic oscillator
model. A proton in a nuclear target is struck by the incident electron and then
propagates through the residual nucleus suffering from soft interactions with
other nucleons. We call the proton "dynamical" when we take into account of
internal excitations, and "inert" when we freeze it to the ground state. When
the dynamical proton is struck with a hard (large-momentum transfer)
interaction, it shrinks, i.e., small-sized configuration dominates the process.
It then travels through nuclear medium as a time-dependent mixture of intrinsic
excited states and thus changing its size. Its absorption due to the soft
interactions with nuclear medium depends on its transverse-size. Since the
nuclear transparency is a measure of the absorption strength, we calculate it
in our model for the dynamical case, and compare the results with those for the
inert case. The effect of the internal dynamics is observed, which is in accord
with the idea of the "color transparency". We also compare our results with the
experimental data in regard of $q^2$-dependence as well as A-dependence, and
find that the A-dependence may reveal the color-transparency effect more
clearly.
