Sentence Pattern:

他是我的爷爷  He is my grandpa ( father's father)

你是我的姐姐  You are my older sister

她是你的妈妈  She is your mother

我是她的妹妹  I am her younger sister

他是她的哥哥  He is her older brother

她是我的外婆  She is my grandma ( mother's mom)

你是我的弟弟  You are my younger brother

我是他们的奶奶 I am their grandma ( father's mom)

她是你们的妈妈 She is your mother

他是我们的外公  He is our grandpa ( mother's father)