... mom is very beautiful
HER mom is very beautiful
She is ...(we) mother
She is OUR mother
Those are ...(they) books
Those are THEIR books
That is ... backpack
That is HIS backpack
This is ... sister
This is HER sister
That is ... twin brother
That is HIS twin brother
... ball is pink
ITS ball is pink
Who is ... (you) sister?
Who is YOUR sister?
I don't like ... (I) shoes
I don't like MY shoes