Gas and dust mass evolution (top and middle panels), and the global dust-to-gas ratio (bottom panel). The plot shows the evolution of a disk with and without the influence of FUV external photoevaporation (black vs. gray lines), for disks with and without a gap-like substructure (solid vs. dotted lines). For this comparison, the disk is around a M_⊙ mass star with an initial size of r_c = 90 AU. The gap substructures are located at r_gap = 1/3 r_c, and the irradiation field is F_UV = 10³ G₀.