单项选择题
A、在山墙内,并距山墙内缘为半砖或半砖的倍数 B、与山墙内缘上相重合 C、自横向定位轴线内移600mm D、自由墙中心线内移600mm
A.450mrn B.600mm C.500mm D.550mm
A.60mm B.50mm C.100mm D.150mm