i find that if you're really stuck on what to write, start of with just thinking about what you want to say- and how you want to say it. formulate a thesis, basically.
then get started on "just writing", which is pretty much all you can do.
i've got my viva coming up in a couple of weeks and i...
An A's an 80 or above right? (That's an a at my school anyway)
I'm not sure about selective schools around the 30's, but at my school (I go to sydney girls) the statistic is that 80% of each year group get an A in every subject.
Don't know if that makes anything clearer...