组: group镜: looking glass; mirror第五组镜头: take five一组镜片: lens三片三组镜头: triplet lens对称式双组镜头: symmetrical doublet lens组距: calss interval; class interval; class inteval; class width; grouinterval; grouping interval; step interval组界再限定: redefinition of group boundary组距大小: magnitude of class interval组界: calss boundary; cla oundary; class boundaries; class boundary组距数值: value of class interval组结构: group structure组距值: class value组接口: gi grouinterface组距中点: class index; class mark组接: assemble
