Sure, we had 5 minutes or whatever short breaks between classes. Though I said that I was "busy" during all periods of free time that I had to spend within the school (lunches, free hours, etc.), so I don't think the distinction matters in this case. :)

(For that matter: I didn't really go to "high school", I'm just using that as the name for my school system's equivalent of year 11 to 13.)