I got problem with my study and exam pls help..?

Your problem is not unique, but I understand your frustration. Some of my best students who always had a good answer in cl and could convey understanding would somehow not read questions thoroughly or something distracted them, hence, they ended up with a C or C - . Even as an instructor, this is quite frustrating for me as well. I know they have a grasp of the information, yet I feel as I have also let them down. I would recommend you not jump to answer exam questions, rather, read them through entirely and think about what you want to say before putting pen to paper. Best of luck to you.