The afterglows of gamma-ray bursts (GRBs) have been commonly assumed to be due to shocks sweeping up circum-stellar medium. However, most of them have been found to be hosting in dense star-forming regions where a significant fraction of the prompt X-ray emission can be scattered by dust grains. Here we revisit the behaviors of X-ray dust-scattering in GRBs. We find that the features of some X-...