单项选择题
A.0.25MPaB.0.3MPaC.0.4MPaD.0.35MPa
A.0.1MPaB.0.15MPaC.0.2MPaD.0.25MPa
A.斜面支撑B.凹槽支撑C.粗糙面支撑D.圆杆支撑