In case you hadn't heard, today the exam boards are publishing their Advance Information on what topics will be the major focus of the Summer exams. It's definitely worth checking out the information on their websites. But also worth noting that it doesn't mean other topics won't come up in the lower mark questions.
Our teens would do well to cover everything if they can. Not only to pick up marks but can you imagine turning over a paper to find the first question is on something you were told not to revise?! That could knock their confidence from the start.