School.

because: He was absent many days because he went back to his hometown.
because of: I didn't finish my homework because of the power outage.
despite: Despite school being closed today, we still need to do homework.
although: Although Kathryn's classes are cancelled today, she went to school at same time this morning.
unless: Unless he passes the midterm, he will fail this quarter.
until: I was studying at library until 9 p.m yesterday.
while: I came to Seattle while I was studying Business Administration in Shanghai.
if: If you work hard, the essay will be finished very fast.
before: I review lessons before I have the midterm.
after: Every day, she still studies at school after her classes.