Sentence:  Thus , a child 's Skeletal Age `` dots '' may <WSD>be</WSD> classified as `` advanced '' when they appear above the middle curve , `` moderate '' when they appear immediately above or below the middle curve , and `` delayed '' when they appear below the lower curve . 
Meaning of the word marked with <WSD> tags:  have the quality of being; (copula, used with an adjective or a predicate noun)