I am one of the tutors for this subject, and a recent graduate from Monash.
In general, most people have done quite poorly on the question of adjusting entries and the last one. The question about sales/inventory is done well by most though.
In the context of what we asked you, the revenue method simply meant that the receiving entity recorded the entire payment of rent as revenue, and correspondingly the adjusting entry would have been to shift the unearned part back into a liability account (unearned revenue). The expense method is similar; the paying entity recorded the whole amount as an expense, and the adjusting entry was to shift the unused portion into an asset account.
I will try to post some tips for this subject if I get the time.