We could not go to the shops today as they closed on Sundays.
couldn't
It is not a good idea to hike today as it is very cold outside.
isn't
Wesley has not got any food to eat.
hasn't
Nathaniel and Welsey are not in grade 3 yet.
aren't
They did not go to the Jump House today.
didn't
Nathaniel does not like tomatoes.
doesn't
He cannot be at the party because he is sick.
can't