  We present two chemical evolution models of our galaxy, both models are built
to fit the O/H ratios derived from H II regions, using two different methods.
One model is based on abundances obtained from the [O III] 4363/5007
temperatures (direct method, DM) and the other on abundances obtained from the
recombination line ratios of [O II/H I] (temperature independent method, TIM).
The differences between the O/H values obtained from these two methods are
about 0.25 dex. We find that the model based on the TIM values produces an
excellent fit to the observational stellar constraints (B-stars, Cepheids, and
the Sun), while the model based on the DM fails to reproduce each of them.
Moreover, the TIM model can explain the flattening of the O/H gradient observed
in the inner disk due to the assumption of an inside-out star formation
quenching, in the 3 - 6 kpc galactocentric range, starting ~ 9 Gyr ago.
