He is doing his best for the defense of the country.

This country is enjoying economic prosperity.

This figure is an acute triangle.

He is learning karate for self-defence.

He works at a public enterprise.

We live in social housing.

This shop is currently open.

Please stand in the center position.

He received an honorable award.

Tridymite, in mineralogy, is a type of silica and is often found in volcanic rocks.