Abundance profiles of molecules CH₃OH, CH₃CN, CCH, and CH₃CCH toward target sources. The symbols are color-coded based on relative distance to the clump center (the 1.2 mm continuum peak). Stars represent abundances at the clump center, and hollow circles or triangles indicate abundances obtained from different radii: the larger and darker these symbols, the closer the distance to the continuum peak. For clump G28 the data points at outer radii are shown as triangles, whereas those for other clumps are shown as circles, to further avoid confusion. X(CCH) for source G10 is taken from Jiang et al. (2015). The inset plot for CH₃CN shows the central abundance vs. gas temperature at 0.1 pc; the plot for CH₃CCH shows the envelope abundance vs. gas temperature at 0.3 pc.