Answer:
"Because it's not our kind of school, stupid".
Step-by-step explanation:
The given excerpt is from a short story called The Fun They Had written by Isaac Asimov. The story is set sometime in the future, when children already have mechanical teachers. A boy named Tommy finds a book about old schools - the schools we have today. He tells about it to Margie. During the conversation, he tells her: "Because it's not our kind of school, stupid". This sentence contains an insult, and based on that we can conclude that Tommy is not a good friend.