spanish subjunctive?

Question

in spanish, what's the difference between the past perfect subjunctive and and the imperfect subjunctive for the "si" clauses?

Answer 1

Si hubiera contestado . . . = if I had answered . . .[PPS]
Si contestara/contestase . . .- if I answered . . .[IS]

After a PPS, you follow with 'hubiese + past participle' meaning 'I would have . . .
After a IS, you follow with a conditional, meaning I would . . .

Hope this helps a bit.