You can't just predict what's coming up. Just learn chunks of everything. What if some person told you 'oh the aimsir chaite is definitley on it'. What if you took their advice and studied just aimsir chaite and the modh coinnioladh showed up? If you pick and choose what to study, you're just screwing yourself up... no offense. Study a bit of ALL grammar, and you'll thank me later. You have a good few months left till the big day: I trust that you will be fine, anyway.