This is especially true for the harder materials of construction.

对于较硬的建材更是如此。

youdao

"You can make materials that are harder or softer," says Matyjaszewski. "Every self-healing material is somehow unique and has advantages over the other ones."

Matyjaszewski说，“材料的制作可硬可软，每种自我修复材料都具有一定的独特性和优越性。”

youdao

Harder, less abrasive materials require slower spindle speeds and softer, more abrasive materials need faster spindle speeds.

哈德，减少研磨材料需要主轴速度慢和软，更磨料需要更快的主轴转速。

youdao

Home-building was more labor-intensive then because of cruder tools and equipment, materials were harder to come by and houses were smaller because they didn't include bathrooms or kitchens.

WSJ: Moving Heaven and Earth for a House��WSJ Mansion

In 1994, North Korea agreed to stop making plutonium, in return for which America and its allies would supply the country with fuel oil and build two Western-designed light-water nuclear reactors (since it is a bit harder to produce weapons-grade materials from such reactors than from the ones North Korea had been building).

ECONOMIST: Not a final deal, just a start | The

TVs and monitors are harder to recycle because of the lead and other hazardous materials they contain.

BBC: Computer mountain graphic