硼：半金属的化学元素，化学符号B，原子序数5。

Boron: Semimetallic chemical element, chemical symbol b, atomic number 5.

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黑的铁氧化物(磁铁矿)：黑的铁氧化物发现有用的，特别在半金属的配方作为提高冷的摩擦力。在半金属的配方的通用的成分。

Black Iron Oxide (Magnetite) Black Iron Oxide is found useful, especially in semi-metallic formulas as an agent for elevating cold friction.

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由于大量原材料，如用于装饰庙宇的半宝石石料、建造屋顶的木材和所有金属都需要进口，贸易变得至关重要。

Trading was important, as so many raw materials, the semiprecious stones for the decoration of the temples, timbers for roofs, and all metals, had to be imported.

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And in the second half of this course, talk to us about transition metals in depth, and that's when we'll really delve into d orbitals.

在这个课程的后半部分，会深入的讲到，过渡金属，这时候，你们可以研究d轨道。

麻省理工公开课 - 化学原理课程节选