bins and roughly no reduction in massive galaxies. The SSFR of the low-mass star-forming sequences in the cluster environment on average reveal a more apparent drop than those in the group environment, indicating that star-forming cluster galaxies are possibly quenched by a slow effect. Assuming that the SSFR of field galaxies is reduced by the amount of suppression seen in the cluster center for low-mass SF galaxies, i.e. 0.2 dex, the $f_q$ of field galaxies increases from $\sim$ 0.54 to 0.71, but it is lower than the center $f_q$ 0.79, implying that the amount of SSFR reduction cannot fully account for the excess in the quiescent fraction relative to the field, and a fast quenching process probably also operate in low-mass cluster galaxies. In addition, at fixed radius, the SSFRs of the star-forming galaxies strongly correlate with the stellar mass, suggesting that the primary factor in determining the SSFRs of star-forming galaxies is their stellar mass, not their location inside groups or clusters.

By contrast, at fixed mass, the SSFRs of all galaxies, including both the star-forming and quiescent galaxies, decrease significantly toward the center for less massive bins and roughly remain roughly constant for massive bins, implying that less 