Here is the completed text with the words from the box:
Hi! My name is John. I'm from London. I'm twelve and I'm at school. School (1) secondary is compulsory in my country. You probably know that there are different types of (2) private schools in Great Britain. Most of them are state schools where education is (3) free. I go to a (4) private school, so my parents have to pay for it. The (5) discipline in my school is very strict. We have to wear a (6) uniform which I don't like at all. What I like most about my school is the (7) opportunity to do sports. We have very strong football and athletic teams and often get prizes in games and (8) competitions.