Considering that there are a number of times, in turn, frequently or does not enroll, consider courses that can make a good grade that are of interest to be taken is to have students enroll?
Considering that the number of open enrollment time or not. Then consider that the course you can do better academic results that are interesting to be an alternative to students to enroll or not.
Considering that there are a number of times in the opening registration often? Then consider that the course can be better grades that are interesting to bring, as an alternative to the enrolled students.