My mother is
my father' s wife .
My father is my mother' s husband .
My mother and my father are my parents .
Mr Smith has got two children : a son and a daughter.
My mother's sister is my aunt .
My father's brother is my uncle .
His brother has got two sons.
They are my father's nephews.
My father has got a sister, too.
His sister has got one child, a daughter.
So, my father has got a niece, too.