硬い

Sono kenkyūjo wa shī-rokujū nano roddo o tsukatte daiyamondo yori katai zairyō o kaihatsu shita.The lab developed a harder material than a diamond by using C60 nano-rods.

Kinchō shite ita no darō ka, kare wa katai hyōjō o shite hōtei ni haitte kita.Perhaps because he was nervous, he entered the courtroom with a serious expression.