Sentence:  The Jazz Three displayed their sound musicianship , not only in their own chosen set , but as the emergency accompanists for Al Minns + Leon James , the superb jazz dancers who have now <WSD>been</WSD> Newport performers for three successive years , gradually moving up from a morning seminar on the evolution of the blues to a spot on the evening program . 
Meaning of the word marked with <WSD> tags:  have the quality of being; (copula, used with an adjective or a predicate noun)