Complete the passage with a suitable preposition

Complete the passage with a suitable preposition
We have English lessons (1) __________ Room 12. There are 24 tables for students and one desk for the teacher. (2) __________ the wall, there are lots of posters of England. There's a cupboard at the front of the room and (3) __________ some bookshelves (4) __________ the classroom. (5) __________ the shelves, there're a lot of English books. Our books are (6) __________ the teacher's desk. He wants to look at our homework. Our school bags are (7) __________ the floor, and there's some food (8) __________ the school bags. It's now 5.30 p.m. We're (9) __________ home, but our teacher is (10) __________ school. He often stays late to prepare for tomorrow's lessons.