方位介词in/on/behind/in front of — 英语填空题
题目
根据句意及中文提示，用方位介词 in / on / behind / in front of 填空。My school is big and beautiful. There is a tall tree ___ (在……后面) the library. Our classroom is ___ (在……里面) the teaching building. The teachers' desk is ___ (在……前面) the blackboard. My ruler is ___ (在……上面) the desk.