1. 金属 五金：mark 标志,商标 | metals 金属,五金 | negotiable 可谈判的,可转让的

2. 材料的类型：材料的类型Types of materials, metals, ceramics, polymers, composites, elastomer | 部分材料性质复习Review of selected properties of materials, | 电导率和电阻率conductivity and resistivity,