Comparison of the N/C and N/O ratios determined from our spectral analyses with predictions from single-star evolutionary models of different masses (Ekström et al. 2012). The primary and secondary stars are shown by the open and filled square symbols, respectively. The left panel illustrates the results for core hydrogen-burning phase tracks without stellar rotation, whilst the right panel corresponds to the same tracks for stars rotating at 0.4 × v_crit.