Sentence:  Only a radical change in the nature of the population in the central city would <WSD>be</WSD> likely to destroy this preference - and we must now turn our attention to the question of whether such a change , gloomily foreseen by so many urban diagnosticians , is actually upon us . 
Meaning of the word marked with <WSD> tags:  have the quality of being; (copula, used with an adjective or a predicate noun)