Sentence:  Nor , when we recollect how sensitive were the emotions of the old Puritan stock in regard to the recent tides of immigration , should we be astonished that their thin lips <WSD>were</WSD> compressed into a white line of rage as Parker snarled at them thus : `` Talk about the Catholics voting as the bishop tells ! 
Meaning of the word marked with <WSD> tags:  have the quality of being; (copula, used with an adjective or a predicate noun)