extramann.机械手extraadj.额外的n.额外之物；临时演员adv.特别地extra heavy pipe特重管,粗管extra deep shaft特深井extraheart sound额外心音extra fine screw特细牙螺纹extramastoiditis[医] 乳突周炎extracirculation外加循环extra-amniotic[医] 羊膜外的extra chromosome超数染色体extraoral cavity口外腔extra absorption额外吸收层