Sentence:  Some recent writings assume that the ignorant young couples <WSD>are</WSD> a thing of the remote , Victorian past ; that nowadays all honeymooners are thoroughly familiar with the best sex-manuals and know enough from talk with friends and personal experimentation to take all the anxiety and hazards out of the situation . 
Meaning of the word marked with <WSD> tags:  have the quality of being; (copula, used with an adjective or a predicate noun)