On possession in English
1. An item owned by two or more persons gets apostrophe on the last item: It’s Kunle, Femi and Wale’s school.
2. Items owned separately by persons get apostrophe after each owner: They’re Kunle’s, Femi’s and Wale’s schools.
3. Apostrophe is used after “else” in the pronoun someone else: Don’t take someone else’s book.
GAB