Reading and then writing a paragraph will have little effect, it really won't stay in your memory for long - same with recording your notes on an ipod, fine for recording a lecture and then copying up notes from it, but simply listening to it will have little effect on your knowledge. You need to actively revise by making yourself learn something. The best way is the old memory game that they play in primary school, write something down, cover it up and attempt to write it again. If you have to cheat for the first few times you can but keep doing it until you dont need to cheat anymore, this will actively reinforce the information and hopefully transfer it into your long-term memory. It really works wonders and is much more effective than passive revision (reading, listening, copying out paragraphs etc).