Sentence:  They lay months away from the nearest Earth star by jump drive , and no one knew what they <WSD>were</WSD> good for , although it was felt that they would probably be good for something if it could only be discovered - much like the continent of Antarctica in ancient history . 
Meaning of the word marked with <WSD> tags:  have the quality of being; (copula, used with an adjective or a predicate noun)