Мы знаем притяжательные местоимения.

I have got a book. My book is very nice.

We have got a nice house.. Our house is far from Moscow.

He has got a sister. His sister is a student.

Существительное в притяжательном падеже / притяжательное существительное (possessive noun) отвечает на вопрос чей? (whose?), обозначает принадлежности одного предмета к другому. Существительные образуют притяжательный падеж при помощи присоединяемой к нему буквы s, перед которой ставится апостроф -     's :

• Mary has got a book.

Her book is nice. Mary’s book is about animals.

• My friends live in the country.

Their house is near the forest. My friends’ house isn’t big.

• Look at the children!

Their mother is my teacher. The children’s mother is an English teacher.

1. The boy has a toy. → It's the ______________________________ .
2. Peter has a book. → It's ______________________________.
3. Our friends live in this house. → It's ______________________________ .
4. John has a sister, Jane. → Jane is ______________________________.
5. This school is for girls only. → It's a ______________________________.
6. Tina has got a brother. There is Tim. → He is ____________________________ brother.

's (Apostrophe, genitive, possessive) – Exercise 3 online >>>

https://www.englisch-hilfen.de/en/exercises/nouns_articles/apostrophe_s.htm

Good Luck!