  We present the detailed modelling of line spectra emitted from galaxies at
redshifts 0.2<z<2.3. The spectra account only for a few oxygen to Hb line
ratios. The results show that [OII]3727+3729/Hb and [OIII]5007+4959/Hb are not
sufficient to constrain the models. The data at least of an auroral line, e.g.
[OIII]4363, should be known. We have found by modelling the spectra observed
from ultrastrong emission line galaxy and faint galaxy samples, O/H relative
abundances ranging between 1.8 X 10^{-4} and 6.6 X 10^{-4}.
