First leg第一站firstadj.第一的；最初的adv.首先；第一n.最初；(序数词)第一First Orbital Flight首次轨道飞行first order analysis一阶弹性分析firsthand impression直接的印象first-prize winner[计] 一等奖获得者first midst and lastadj.始终(一贯；彻头彻尾)first-order factor一次因子first order kinetics一级消除动力学first three quarters前三个季度First order sea echo一阶海洋回波first-degree crime一级犯罪