Sentence:  The concertos that Van Cliburn has been associated with in New York since his triumphant return from Russia in 1958 have <WSD>been</WSD> the Tchaikovsky , the Rachmaninoff Third , and the Prokofieff Third . 
Meaning of the word marked with <WSD> tags:  have the quality of being; (copula, used with an adjective or a predicate noun)