Bonjour,
Réponse :
1 - The boy likes his school. ( son : his / possesseur masculin )
2- The teachers park their cars in front of the school.
3- The cat always eats its food quickly. ( sa : its / possesseur neutre )
( Remarque "cat" est un animal domestique, on peut donc mettre "his" food si l'on veut montrer son attachement à celui-ci )
4- I often forget my keys.
.5- She likes giving presents to her grandchildren. ( ses : her / possesseur féminin )
6- You never write on your books.
7- We always eat our lunch at 12 o'clock
8- They never do their homework