Collagen is important for maintaining the firmness and elasticity of the skin.

Watching a movie alone is enjoyable.

My younger brother is a first-year student of an elementary school.

This perfume uses expensive ambergris.

This epidemic is spreading all over the world.

This perfume contains ambergris, an expensive ingredient.

His disease has spread to his vital organs.

This mineral is called anhydrite.

His resounding voice echoed throughout the room.

The ringing sound of the bell filled the quiet night sky.