Sentence:  When they got home Harold <WSD>was</WSD> grateful for the stillness in the apartment , and thought how , under different circumstances , they might have stayed on here , in these old-fashioned , high-ceilinged rooms that reminded him of the Irelands ' apartment in the East Eighties . 
Meaning of the word marked with <WSD> tags:  have the quality of being; (copula, used with an adjective or a predicate noun)