if you get started you can, you palm, the pattern comes back and you follow it through and you get the answer, erm, need to do it every, maybe sort of about once a month or so, for each topic, don't let a topic go for about a month without you looking at it for ten minutes or so, and it will be surprising how that little bit of effort keeps it in your mind, so when you come to the exam you don't sit down there and go, oh, it's two months ago, I was doing everyone right, wonderful