  A Lagrangian of electroweak interactions without Higgs is used to study the
contributions of quarks and leptons to the masses of the W and the Z bosons. It
is shown that the $SU(2)\times U(1)$ symmetry is broken by both fermion masses
and axial-vector components of the intermediate bosons. The masses of the W and
the Z bosons are obtained to be (m^{2}_{W}={1\over2}g^{2}m^{2}_{t}) and
(m^{2}_{Z}=\rho m^{2}_{W}/cos^{2}\theta_{W}) with (\rho\simeq 1). Two fixed
gauge fixing terms for W and Z boson fields are derived respectively. A
coupling between photon and Z boson is predicted. Massive neutrinos are
required.
