Complex sentence: Students at each grade level are required to take the general English class for that grade level, which is a full-year course that can be taken at the comprehensive, college preparatory, or advanced levels with Advanced Placement available in 12th grade.
Split into simpler sentences: Students at each grade level are required to take the general English class for that grade level. Required English courses are full-year classes that can be taken at the comprehensive, college preparatory, or advanced levels with Advanced Placement available in 12th grade.