I actually have the same question. I only had two exams last January, and I got 99% in one and 100% in the other; if you have a small number of exams and paid attention during the term, there's not really much of an excuse for not doing as well as you're capable of. (Of course, there are some people who wouldn't be capable of an A even if they did every past paper known to man and copied out the textbook three times a day.)