计算:a3•a4等于( )
A.a7
B.a12
C.3a4
D.4a3
a3•a4=a7.
故选A
The boy is lying on the ground, _________ at the aeroplane in the sky.
A.looked
B.looking
C.look
D.to look
A县级以上地方各级人民政府统计机构做出的具体行政行为不服,必须向其上一级人民政府统计机构申请复议。()