If a dog is lying on a couch with its head down.
return dog ;return couch ;return #1 that is lying on #2 ;return head of #3 ;return #3 where  #4 is down ;return number of  #5 ;return if  #6 is at least one
['select', 'select', 'filter', 'project', 'comparative', 'aggregate', 'boolean']