  A possible generalization of the technique of the standard model to
$SU(n)\otimes U(1)$ gauge models is proposed. A special Higgs mechanism and a
new kind of Yukawa couplings in unitary gauge are introduced. These allow us to
obtain a general method of deriving boson mass spectrum and coupling
coefficients which will be used to find an exact solution of the Pisano-Pleitez
three-generation $SU(3)\otimes U(1)$ model. A new anomaly-free one-generation
model is briefly discussed.
