A blue supergiant is one of the brightest stars in the universe.

He is working as a clergyman in the church.

He was diagnosed with mental illness.

There are times when we perform calculations with the haversine in trigonometry.

He is a pessimist, always looking at the bad side of the world.

This regular tetrahedron is composed of equilateral triangles on all sides.

He made a model of a regular tetrahedron.

He likes to take a walk in the park at dusk.

My father works at a paper mill.

My father has been working as a silk manufacturer for many years.