问题
The one _________ me is writing on the blackboard ________ the classroom
A:behind ; in front of
B:behind; in the front of
C:at the back of; in front of
D:at the back of ; in the front of;
B:behind; in the front of
C:at the back of; in front of
D:at the back of ; in the front of;
正确答案是：
