Parameter spaces for NS+MS, NS+HG, and NS+GB binaries that can produce sdB+NS binaries, where M₂ is the companion mass and P_m is the orbital period when the companion fills its Roche lobe. M₂ ranges from 0.8 M_⊙ to 5.0 M_⊙ (MS stars with mass > 5.0 M_⊙ could soon evolve to high-mass X-ray binaries through accretion by the stellar wind). The regions enclosed with the solid and dashed lines are for the stable RLOF channel and the CE ejection channel, respectively. In the CE channel, α_CE = 1. The results for α_CE = 0.5, 2, and 3 are shown in Fig. 3.