first aid急救firstadj.第一的；最初的adv.首先；第一n.最初；(序数词)第一First - derivative spectrometry一阶导数光谱法first integral mean value theorem积分第一中值定理First-class sports provincially体育强省first-aid patients in emergency急诊急救病人first countable topological space第一可数拓扑空间first-in first-out discipline先进先出项目first generation industrial robot第一代工业机器人First of two possible upgrades.二个可能的升级第一。first arrival tomographic statics初至层析静校正First Aid Technical Stores Outfit急救技术性补给品装备

1. There is a very high tariff on jewelry.
   宝石的税率很高。
2. The first part introduces the selection between the proportional tax rate and the progressive tax rate.
   第一部分是关于个人所得税税率形式在比例税率与累进税率之间的选择。