平面广告是一种（）广告形式。
A.二度空间
B.时间的
C.三度空间
D.空间的
参考答案：A
21. He apologized ________ late.
A．to his teacher to arrive
B．to his teacher for arriving
C．at his teacher to arrive
D．at his teacher for arriving
农产品价格合理化的意义？
