Условие задания:

3 Б.
Write the correct possessive form of the word in the gaps. (Напиши правильную притяжательную форму слова в скобках.)
 
For example
These are the ________ books (girls).
These are the girls' books.
  
1. The  room is on the second floor (children).
 
2. These are the  pencils (pupils).
 
3. It's my  house (grandparents).