An alien is hiding ... the rock.
behind
He is ... the roof
on
He is ... the car.
in
There's a bookcase ... two beds.
between
She is sitting ... a rock.
on
She is sitting ... a rock.
on
He is ... the box..
in
A tiger is ... a cat.
next to
There's a tree ... the house.
in front of
There's an armchair ... the window.
next to
Throw the litter ... the rubbish bin.
in
There's a wooden house ... the trees.
between / next to
Let's relax ... the fireplace.
next to / in front of
There are nice flowers ... the table
on
A woman is standing ... the sea.
in front of
There are presents ... the tree.
under
The girl is reading ... the tree.
under
The cat is ... the bed.
under
The kitten is sitting ... the box
in
The dog is ... the table.
under
There are a lot of books ... the shelf.
on