Theastronautssucceeded_______fromthemoontotheearthaccordingtotheplan.A.inreturningB.inreturningback我知道succeedin并且介词后面跟ing但是为什么不能加back?难道是固定搭配?

　　Theastronautssucceeded_______fromthemoontotheearthaccordingtotheplan.A.inreturning

　　B.inreturningback

　　我知道succeedin并且介词后面跟ing但是为什么不能加back?难道是固定搭配?