What's this number?
fifteen
Who is this?
It's my sister.
What's this number?
twelve
Who's that?
It's my mother.
Who is this?
It's my father.
Is this your sister?
Yes, it is.
Sister
Brother
Is that your father?
No, it isn't.
Is that your mother?
No, it isn't.
Is this your brother? (Yes)
Yes, it is.
Father
Who's that?
It's my brother.
Mother