The study is one of the issues that can make the students the same headache. For example, it was homework examples. Classrooms and don't understand. The exam is not. The exam is not passed. Bad grades
The problem is one that can cause headaches, students have little in common, such as the home to the room and I do not understand, do not pass exams, not bad grades.
Learning is the problem that one can make the students have a headache not same. Such a lot of homework. Study room, and don't understand. The test does not pass the examination. Bad grade.