A number of important problems concerning relaxation processes of the system are discussed, such as relaxation mechanism of intramolecular V-V processes in CO2,mechanism of significant effect of H2O on relaxation,resonant energy transfer between v1 and v2 modes of CO2, identity of relaxation data in compression, and expansion flows and possible nonequilibrium, among different vibrational levels in a mode and different rotational levels in a vibrational level. Problems that need further exploration are presented. This discussion is also found to be applicable to other laser systems.