单项选择题
A.每3km抽检3处,每处测3点 B.每5km抽检3处,每处测5点 C.每5km抽检5处,每处测2点 D.每5km抽检3处,每处测3点
A.0.5mm B.0.3mm C.0.2mm D.0.1mm
A.0.5mm B.0.8mm C.0.6mm D.0.9mm