Comparison with the composite of all VUDS star-forming galaxies (Sample C; yellow-filled pentagon) and the best fit model (red open diamond). The model is provided by the BPASS-300bin incident radiation with Z = 0.33 Z_⊙, log U = −2.75, and the age of 100 Myr. In the two EW plots, a red cross presents the best-fit model at 1 Myr as derived directly from the plotted model tracks. The decrease of EW by × 3.3 and × 3.5 corresponds to the age effect for the [CIII] and CIV, respectively, if the longer star-formation age of 200 Myr is adopted (Fig. 6).