A.10cmB.15cmC.20cmD.25cm
A.極坐標(biāo)法B.前方交會(huì)法C.后方交會(huì)法D.軸線(xiàn)交會(huì)法
A.0.5~0.9mB.0.8~1.5mC.1.0~2.0mD.1.5~2.5m