参考例句：
Indentation methods of hardness testing comprise two principal groups
压痕法测定硬度包括两大类。
The softer rock wears away.
硬度较低的石头磨光滑了。
degree of hardness and elasticity of a tempered meta
（金属回火后的）硬度和弹性.
Once a satisfactory system of lubrication has been secured the hardness of the interacting elements becomes critical.
一旦获得了满意的.润滑系统，相互作用的元件的硬度就成为紧要之事。
A moderately hard variety of pewter.
白?中等硬度的白?
Pencils are graded according to softness.
铅笔根据硬度分类。
With regard to hardness, the diamond is in a class by itself.
讲硬度，金刚钻是独一无二的。
The temper of steel is higher than that of aluminium.
钢的硬度比铝高
。Minerals usually differ in hardness.
矿物的硬度往往不一样。
Cone imprint
(硬度试验器)锥印痕
hardness是什么意思：
n. 坚硬；困难；冷酷
It is hard to conclude.
这很难断定。
It is blowing hard.
风刮得很大。
It was sleeting hard.
雨雪霏霏。
To bear hard upon;press.
使痛苦不堪对某人施加困难；逼迫
press hard upon
进逼|压迫|穷追