Sentence:  The history of disarmament agreements , for instance , had <WSD>been</WSD> unreassuringly dismal ; but the United States and the Union of Soviet Socialist Republics nevertheless did eventually agree on an atomic bomb test ban , and a sort of provisional acceptance of each other 's good intentions on this limited question . 
Meaning of the word marked with <WSD> tags:  have the quality of being; (copula, used with an adjective or a predicate noun)