Sentence:  Thus Burns 's `` My love <WSD>is</WSD> like a red , red rose '' and Hopkins ' `` The thunder-purple sea beach , plumed purple of thunder '' although clearly intelligible in content , hardly present ideas of the sort with which we are here concerned . 
Meaning of the word marked with <WSD> tags:  have the quality of being; (copula, used with an adjective or a predicate noun)