Question: What are the outflow of the lakes which also has one of the outflow as Congo River?
SPARQL query: SELECT DISTINCT ?uri WHERE { ?x <http://dbpedia.org/property/outflow> <http://dbpedia.org/resource/Congo_River> . ?x <http://dbpedia.org/ontology/outflow> ?uri  . }
Answer: The outflows of the lakes whose one of the outflow is Congo River are [Nile, Congo River, Benué River, Zambezi].