Sentence:  But then , Mario Lanza was no common singer , and his whole career , public and non-public , was studded with the kind of unconventional happenings that terminate with the appearance of his first `` recital '' only when he has ceased to <WSD>be</WSD> a living voice . 
Meaning of the word marked with <WSD> tags:  have the quality of being; (copula, used with an adjective or a predicate noun)