  We, basing on the quantum critical point (QCP)($p = 0.19 $), propose a
phenomenological description on high-$T_c$ superconductivity in the cuprate
superconductors, and suggest it divides the whole doping region into two parts:
the underdoped region ($p < 0.19 $) and the overdoped region ($ p> 0.19 $). The
electrons in the former are localized and form the localized Fermi liquid, a
kind of the non-Fermi liquid, where the carriers are the holes; the electrons
in the latter are itinerant and form the Fermi liquid, where the carriers are
the electrons.
  We further argue that localization is a prerequisite to the pseudogap; the
superconductivity gap and coherence forms at the same time, which both share
the same energy scale; coherence induces phonon around the node.
