My younger sister is nineteen years old.

My younger sister is eighteen years old.

The thirteenth day of the month is my birthday.

Crux is one of the constellations in the southern hemisphere.

He gripped the control stick and piloted the plane.

Heavy hydrogen is one of the isotopes of hydrogen.

He perfectly memorized the fifty sounds.

Because of his indecisive nature, he always takes a long time to choose a menu at a restaurant.

He was playing video games all day.

He was surrounded by his family when he was on his deathbed.