If there is a set of white pearl earrings made out of a safety pin with round copper backing.
return pearl earrings ;return #1 that are white ;return safety pin ;return #2 made out of #3 ;return backing of #4 ;return #4 where  #5 is round ;return #4 where  #5 is copper ;return #4 in  both  #6 and #7 ;return number of  #8 ;return if  #9 is equal to  two
['select', 'filter', 'select', 'filter', 'project', 'comparative', 'comparative', 'intersection', 'aggregate', 'boolean']