The teacher's desk is ( )the blackboard in the classroom.

答案：D in front of
解释：
1. in the front of 指“在某一物体内部的前面”.比如：
There is a big desk in the front of the classroom.
在教室的前部有一张大桌子.
2. in front of 指“在某一物体外部的前面”,比如：
Can you see a red car in front of that house?
你能看到那所房子前面的一辆红色汽车吗?
祝你学习进步,更上一层楼!(*^__^*)