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 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.