My younger sister is seventeen years old.

He is learning self-defense techniques using a jutte.

He is collecting a rare jitte.

He is studying the shape of a decahedron.

My grandfather is seventy years old.

My grandfather is ninety years old.

My grandfather is already eighty years old.

He read scores of books.

When I was in my teens, I used to play soccer every day.

My father is forty years old.