elementary, 4 a grammar

Monica Cruz is Penelope's siste / sister's Penelope.

• Penelope's sister

• sister's Penelope.

It's my mother's birthday / my birthday's mother.

• mother's birthday

• my birthday's mother

That's her parent's house / her parents' house.

• her parent's house

• her parents' house.

I'm tired when I go home at the end of the day/the day's end

• the end of the day

• the day's end

Those are friends' my sister/ my sister's friends.

• friends' my sister

• my sister's friends.

The door of the classroom / The classroom's door is open.

• The classroom's door

• The door of the classroom

Those are the students' desks / the desk's students.

• the students' desks

• the desk's students.