There is a pen on the table
there isn't a pen on the table
is there a pen on the table?

there are books in the box
there aren't books in the box
are there books in the box?

there was a horse in the farm
there wasn't a horse in the farm
was there a horse in the farm?

there were books on the desk
there weren't books on the desk
were there books on the desk?

there were many students in the classroom
there weren't many students in the classroom
were there many students in the classroom?