human
Find buildings whose construction year is not specified.
gpt
```sparql
PREFIX :       <http://example.org/ontology#>
PREFIX rdf:    <http://www.w3.org/1999/02/22-rdf-syntax-ns#>

SELECT ?building
WHERE {
  ?building rdf:type :Building .
  FILTER NOT EXISTS {
    ?building :hasConstructionYear ?year .
  }
}
```