extra fee额外费用
extraadj.额外的n.额外之物;临时演员adv.特别地
extracurricular reading material课外读物
extraordinarily high temperature超高温
extracurricular sports exercises中学生
extra fine stainless steel wires极细丝
extra-cavity resonant doubling外腔谐振倍频
extracellular protease secretion胞外酶分泌
extrahepatic biliary obstruction肝外胆管梗阻
extraembryonic capillary network胚外毛细血管网
extra-adrenal pheochromocytoma肾上腺外嗜铬细胞瘤
extrachromosomal genetic element染色体外遗传因子