Change of the C/N and N/O ratios on the surface of the models given at seven different times in the evolution; at the zero-age main sequence (ZAMS), half-way the main sequence (MMS), at the terminal-age main sequence (TAMS), on the Hertzsprung gap (HRG), and at the onset of helium burning (ZAHeB). The symbols are for the different values for α_ov while the colours indicate the different amounts of log(D_env/cm² s⁻¹) in the same way as in the previous figures.