Some are full year classes, others are half. My math, science, history, foreign language, and PE classes were full-year, five days a week. We took 2 half-year English classes each year from 10-12 grades (9th grade English was full-year) that we got to choose the subject of, from English or Brit lit to creative writing and journalism classes, so everyone ended up taking seven different English classes over 4 years.
Health, art, music, home ec, shop and so on were each half-year classes, and you took as many as required for graduation -some could be avoided as you had take art or shop but could take both - and had study hall if you were finished the requirements and didn’t ask to take an extra elective.