Form structures 3 - Choice

    @prefix foaf:  <http://xmlns.com/foaf/0.1/>.
    @prefix sched: <http://www.w3.org/ns/pim/schedule#>.
    @prefix cal:   <http://www.w3.org/2002/12/cal/ical#>.
    @prefix dc:    <http://purl.org/dc/elements/1.1/>.
    @prefix rdfs:  <http://www.w3.org/2000/01/rdf-schema#>.
    @prefix ui:    <http://www.w3.org/ns/ui#>.

    @prefix schema: <http://schema.org/>.

    @prefix trip:  <http://www.w3.org/ns/pim/trip#>.
    @prefix vcard: <http://www.w3.org/2006/vcard/ns#>.
    @prefix xsd:   <http://www.w3.org/2001/XMLSchema#>.
    @prefix ex: <#>.  # Things in the examples
    @prefix : <#>.