The electroweak theory of SU(3) $\times$ U(1)
  An electroweak model of SU(3) $\times$ U(1) gauge group is studied. {}From the group theoretical constraint, the symmetry breaking of this model to the standard model occurs at 1.7~TeV or lower. Hence the mass of the new neutral gauge boson is less than 1.7 TeV. The $Y^\pm$ and $Y^{\pm\pm}$ masses are found to be less than half of the $Z_2$ mass. Thus, the decays $Z_2 \to Y^{++} Y^{--}$ with $Y^{++} \to 2\ell^+ \: (\ell \!=\! e,\mu,\tau)$ is allowed, providing spectacular signatures at future colliders. {}From the flavor-changing neutral current processes, the representations of quarks can be uniquely determined. The neutrino-isoscalar scattering experiments are also considered. 
Daniel Ng