Sentence:  It <WSD>is</WSD> significant that the Catskills , which used to be the summer playground for older teen-agers , a kind of summer suburb of New York , no longer attracts them in great numbers - except for those who work there as waiters , bus boys , or counselors in the day camps . 
Meaning of the word marked with <WSD> tags:  have the quality of being; (copula, used with an adjective or a predicate noun)