Sentence:  <WSD>Being</WSD> a teacher of American literature , I remembered Whittier 's `` Massachusetts to Virginia '' , where he said : `` But that one dark loathsome burden ye must stagger with alone , And reap the bitter harvest which ye yourselves have sown '' . 
Meaning of the word marked with <WSD> tags:  have the quality of being; (copula, used with an adjective or a predicate noun)