For the most difficult subjects. I think that is a major cost because my friends have mentioned the difficulty of the subject. There is poverty makes many people stuck F.
For the most difficult subjects I think the cost of Because a friend of mine mentioned the difficulty of the course. There are so many poor people trapped F.
For the most difficult subject, I think the course is the cost. Because of my friends have mentioned the difficulty of a course. There are many F poverty make stick.