We have shown that the unconventional temperature dependence of the st
atic susceptibility chi(T) of the perovskite high-T-c superconductors
above the superconducting transition temperature T-c can be explained
in terms of two relevant band models containing the singlet-correlated
oxygen band and the copper character band. The usual copper-oxygen Ha
miltonian containing hopping and Coulomb repulsion terms has been redu
ced to an effective Hubbard-like t - t' - t '' - U-eff model to descri
be the low-energy properties. The unusual behaviour of the susceptibil
ity is due to thermally activated oxygen holes coming into the hybridi
zation singularity peak in the density of states. A possible physical
origin of T-max in the temperature dependence of the susceptibility is
discussed.