Sentence:  And the bed that sagged in a certain place where all the weight had been put too many times before and the walls fine and thin for overhearing talk in the next room when Gratt went out for ice , the sound coming through the walls like something on the other side of the curtain , so you knew they heard you when they <WSD>were</WSD> quiet and while you lay wondering what they had heard you listened . 
Meaning of the word marked with <WSD> tags:  have the quality of being; (copula, used with an adjective or a predicate noun)