@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .
@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
@prefix owl: <http://www.w3.org/2002/07/owl#> .
@prefix ex: <http://example.org/> .

ex:A rdfs:subClassOf owl:Thing .
ex:A rdf:type owl:Class .
ex:B rdf:type owl:Class .
ex:B rdfs:subClassOf ex:A .
ex:C rdf:type owl:Class .
ex:C rdfs:subClassOf ex:A .
ex:D rdf:type owl:Class .
ex:D rdfs:subClassOf ex:A . 