There are many pictures on ( )

问题描述:

There are many pictures on ( )
A,the classroom's walls
B,the walls off the classroom
C,the wallls in the classroom
应该选哪个,为什么?
B,the walls off the classroom
改为B,the walls of the classroom

选C,指教室的墙上
A 是教室所属的墙上
B 里的off应为of