PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> 
PREFIX  foaf:       <http://xmlns.com/foaf/0.1/>

CONSTRUCT { _:a rdf:subject ?s ;
                rdf:predicate ?p ;
                rdf:object ?o  . }
WHERE {
  ?s ?p ?o .
}