Top: C iiλ 4267.09 Å line in a simulation (with an assumed K_sec = 230 km s^-1). φ is the orbital phase. The transit (φ = 0.0) and the occultation (φ = 0.5) of the secondary are simulated. Bottom: same line in our X-Shooter observations. In the online version, the red spectra show the occultation of the secondary. In the blue spectra, C iiλ 4267.09 Å is prominent. The vertical (green) bar indicates the rest wavelength of the line.