Нужно вставить форму глагола (to be) 1.we very good frieds. 2.where you from? they from russia. 2.where the books? they ln the bookcase 3.she my sister. she 8 yers old

We are very good friends.
Where are you from? They are from Russia.
Where are the books? They are in the bookcase.
She is my sister. She is 8 years old.