Sentence:  Since she could not act , one part suited her as well as any other , and so she <WSD>was</WSD> the first person to offer Mr. Lincoln a glass of water , holding it up to the box , high above her head , to Miss Harris , who had asked for it . 
Meaning of the word marked with <WSD> tags:  have the quality of being; (copula, used with an adjective or a predicate noun)