Sentence:  This scene is a `` white ballet '' in which a lovelorn hero searches for his departed love 's spirit among twenty-eight extraordinarily beautiful `` shadows '' who can all dance like nothing human - which , of course , <WSD>is</WSD> altogether fitting . 
Meaning of the word marked with <WSD> tags:  have the quality of being; (copula, used with an adjective or a predicate noun)