Sentence:  `` This is a long picture and a controversial one , but basically it <WSD>is</WSD> a moral , enthralling and heartbreaking description of humans who have become unlinked from life as perhaps Rome has from her traditional political , cultural and religious glories '' . 
Meaning of the word marked with <WSD> tags:  have the quality of being; (copula, used with an adjective or a predicate noun)