Hi, I'm Liu Ying. This is my school. It's big and beautiful. There are twenty classes. There are nine hundred students in my school. There are four beautiful gardens in it. There is a building in my school. On the first floor, there are two offices and a hall. There are six classrooms on the first floor, too. On the second floor, there are fourteen classrooms. There are two toilets on the second floor. There is a big library and some reading rooms in my school, too. How many classes are there in the school?
Ten Fifteen Twenty fifty