saleh, that's the point. When we study law, we have to learn the skill of finding what both sides can argue.So having someone else provide one side's argument, or part of it, doesn't help.With practice you'll find arguments which nobody has thought of. In a law practice you'll still be doing that, and nearly all of them will be untenable. Then you have to learn to spot the ones that look untenable but which are right !
At a more advanced level ,in practice, you have to spot the ones that can be established on the evidence. Plenty of good arguments can be seen on the agreed facts in an exam question. Unfortunately, real cases depend on human beings giving evidence. You need to judge what the evidence will sound like when they give it, how credible it will sound after they've been cross-examined, if indeed they 'come up to proof', that is say what you think they are going to say !