Sentence:  But while she <WSD>is</WSD> able to tell her retarded family about the new world she has seen open before her , Ronnie has not been able to observe her progress , and instead of appearing at a family party to be looked over like a new bull , he sends Beatie a letter of dismissal . 
Meaning of the word marked with <WSD> tags:  have the quality of being; (copula, used with an adjective or a predicate noun)