Just talk 说说
Look! This is my father and this is my mother. 看!这是我爸爸,这是我妈妈。
Who's this? 这是谁?
This is my grandmother. 这是我祖母。
And who's that? 那是谁?
That's my grandfather. 这是我祖父。
Just learn 学学
grandfather(grandpa) 祖父
grandmother(grandma) 祖母