景别主要由什么决定（）
A.镜头焦距
B.拍摄距离
C.拍摄角度
D.景物自身
参考答案：A, B
_____ that he isn't adequate to the present job, he devotes all his spare time to studying professional
knowledge. [ ]
A. Concern
B. To concern
C. Concerned
D. Concerning
单项式-2008a3bm与单项式3anb是同类项，则（-m）n=______．
