A.+1 B.-1 C.0 D.∞
A.0.9m B.1.8m C.2.7m D.3.6m
A.發(fā)散入射同心光束的頂點(diǎn) B.會(huì)聚入射同心光束的頂點(diǎn) C.發(fā)散出射同心光束的頂點(diǎn) D.會(huì)聚出射同心光束的頂點(diǎn)