No one can predict for you the questions that you would have to answer in OPSC OAS examination. If some one can do that, you are the one. So candidate has to develop the foresightedness to predict for him/herself. And this foresightedness could be developed through the process of picking up vital clues from the past year question papers.
If candidate carefully go through the previously asked questions, they can very easily make out a list of topics or areas from where questions are primarily framed in a particular subject. After identifying such hot shot areas, candidates can themselves frame a few probable/ model questions. While framing questions, candidates must make sure that they are not leaving out any important aspect of that topic, that is how a candidate can became a predictor for him.herself.
Past year questions papers are easily available in internet (www.objectiveias.in). Even solved questions papers could be seen on the internet or market. But before following these solved papers you have to remember few things such as: He/she must not try to by-heart those answers because imitation of those answers is not going to fetch god marks. Such answers can only provide a general idea about answering, the questions and some times, quite important facts may also be present in them.
Therefore, through carefully picking up the vital clues provided in previous years questions papers, candidates may make indicative predictions to get hold of their own probables.