Practice manual problem

FRIENDS, I am very confused..not able to clear 2nd GRP of IPCC problem is it sm and audit I never got more then 45 in above subjects. every1 is suggesting to prepare both these subjects with practice manuals study mat ect. the problem is while studying from practice manuals of the above subjects I found the language tough. I am able to understand only 40 to 50 per that to with some efforts because of past understanding of these subjects. I found other teachers books in the market which are easier than pm. I didn't get a good feeling and confidence that I could be able to write this lang of pm in exams. my query is that whether I should stick on pm as these are highly recommended by toppers and many people or I should enhance my knowledge and write the answers accordingly. please guide me. thanks