When we have something it is called possession.
An apostrophe is a punctuation mark '
When we talk or write about something that belongs to someone else, rather than saying:
This is the dog that belongs to Ben.
we would say
This is Ben's dog.
Did you spot the apostrophe after the word Ben? The apostrophe tells us that the dog belongs to Ben.
or
This is the sandwich that belongs to Mary.
we would say
This is Mary's sandwich.
Did you spot the apostrophe after the words Ben and Mary? The apostrophe tells us that the dog belongs to Ben, and the sandwich belongs to Mary.
We are going to have a go at rewriting some sentences to show possession.