I can see a/an Halloween celebration
a
They are/aren't in the woods
are
I think they enjoy/are enjoying the party
are enjoying
There is some/a haunted house
a
They enjoy walk/walking in the woods
walking
The first boy is holding some/a ball
a
It is night/morning/afternoon
night
The pumpkins are in front of/behind the haunted house
in front of
There is/are a full moon
is
This photo show/shows a group of friends wearing costumes
shows
Some/any bats are flying in the sky
some
There aren't any/some zombies
any