extra arm外臂, 可变臂extraadj.额外的n.额外之物；临时演员adv.特别地extra-linguistic factors超语言因素extra high water cut stage特高含水期extragalactic radio source核外射电源extrapyramidal involvement锥体束外受累extramedullary hematoposis髓外造血extrapleural thoracoplasty胸膜外胸廓成形术extracharge on long length超长货物附加费extramedullary hemopoiesis髓外造血extracurricular activities课外活动extra-high tension probe极高压探头