In the last year of high school I feel sad heart because it is the last year that I will be able to live with a friend, together with an eye to each other before they disperse to study in a University.
In the final year of secondary school I felt sad because last year I will be a reunion with friends before everyone dispersed to study at the university level.
In the final year of secondary school students, I feel sad because, as last year I was with friends together before they split up to study in college students.