Hi Inma,
This lesson says that sometimes haber in the imperfect subjunctive can replace haber in the conditional; but doesn't say when. I had a tutor in Mexico who claimed (that least in some cases) the construction had to be hubiera....hubiera; whereas a Mexican friend said the construction is always hubiera.....habría or vice versa depending on which clause comes first. This lesson seems to say you can replace habría with hubiera in this construction if you feel like it. Can you clarify this for me, please?