单项选择题
A.180mm;50mm B.150mm;50mm C.180mm;20mm D.150mm;20mm
A.安全员证 B.特种作业上岗证 C.指挥证 D.特种作业资格证
A.1.8m;200mm B.1.5m;300mm C.1.5m;400mm D.1.8m;500mm