What are some cars which came before the ones on a GM B base?
SELECT DISTINCT ?uri WHERE { ?x <http://dbpedia.org/ontology/automobilePlatform> <http://dbpedia.org/resource/GM_B_platform> . ?x <http://dbpedia.org/ontology/predecessor> ?uri  . ?x <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://dbpedia.org/ontology/Automobile>}
GM_B_platform