Halform三卤甲烷halfn.一半；下半场；半学年adj.一半的；不完全的adv.一半地；不完全地half-value thickness半值层,半吸收厚度,强度减半厚度half-cell potentials半细胞电位half mean spring range大潮平均半潮差half-embedding crack半埋藏裂纹half-duplex repeater半双工中继器half-echo suppressor半回声抑制器half-infinite matrix半无穷矩阵half cylinder absorber半圆柱接收器half-mask respirator半面罩式呼吸防护器half pedestrian street半步行街