Is there a bed behind the bookshelf?
No, there isn't. There is a bed next to the bookshelf.
What is it?
It is a clock.
Is there a bed in front of the bookshelf?
Yes, there is.
There is a table....... the chair.
in front of
There is a table ..... the sofa.
behind
There is a bookshelf......... the table
next to