Sentence:  I have just asked these questions in the Pentagon , in the White House , in offices of key scientists across the country and aboard the submarines that prowl for months underwater , with neat rows of green launch tubes which contain Polaris missiles and which <WSD>are</WSD> affectionately known as `` Sherwood Forest '' . 
Meaning of the word marked with <WSD> tags:  have the quality of being; (copula, used with an adjective or a predicate noun)