My younger sister is twenty-two years old.

There are innumerable books in his room.

My hamster is very cute.

Williams is my best friend.

He is a distinguished person in his field.

The debtor has an obligation to repay his debt.

My grandfather is already sixty years old.

When summer vacation comes, the children enjoy bug catching every day.

When summer vacation comes, children become engrossed in insect collecting.

When summer vacation comes, children enjoy collecting insects in the park.