用来做工具的主要材料可以被分为三大类：黑色金属材料，有色金属材料，非金属材料。
The principle materials used for tools can be divided into three major categories: ferrous material, nonferrous material, and nonmetallic material.
准金属，类金属具有一些金属化学特性的非金属元素，例如砷。
A nonmetallic element, such as arsenic, that has some of the chemical properties of a metal.
在金属和非金属这两类物质中，很可能金属总是更为重要的一种。
It is likely that metals will always be the more important of the two groups: metals and nonmetals.
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