  The generic band structure of high-T$_C$ copper oxides is simulated by the
nearly free-electron model (NFE) in two dimensions (2-D) with parameters from
band calculations. Interaction between phonons and spin waves will cause
potential modulations and pseudogaps, and the strength of the modulations, the
wave lengths and the doping, are all related. A Fermi-surface "arc" is found
for dynamic spin/phonon waves. The confinement of superconductivity between two
limiting dopings can be a result of competition with the pseudogap at low
doping and weak coupling at high doping.
