If there are two dogs standing on four legs.
return dogs ;return legs of #1 ;return #2 that #1 are standing on ;return number of  #3 for each  #1 ;return #1 where  #4 is equal to  four ;return number of  #5 ;return if  #6 is equal to  two
['select', 'project', 'filter', 'group', 'comparative', 'aggregate', 'boolean']