  The spectra and form factors of exclusive semi-leptonic decays of B-meson are
analyzed, taking account of confined effects of quarks by the Covariant
Oscillator Quark Model. The predicted B --> (D*,D)l nubar_l spectra with the
conventional value of V_cb are fit well to the high-precision experiment. It is
also shown the values of V_cb and V_ub obtained through decay widths for the B
--> (D,D*,rho)l nubar_l processes are consistent with the presently accepted
ones.
