Another quality of line that's more difficult to achieve is variation in the softness and hardness.

线的另一性质更加难以企及，那便是软硬的变化。

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Last, Nanzheng Serpentine's quality evaluation was infected by it's structure, component, color, transparence, hardness, resilience and size and it's the foreground of developing was prospected.

最后从结构、成分、颜色、透明度、硬度、韧度及块度等对南郑蛇纹石玉进行了客观分析及质量评价，并对其开发前景进行了展望。

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Cast iron manhole cover of good quality is to see its toughness and hardness.

质量好的铸铁井盖是要看其韧度和硬度的。

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