Sentence:  A few drops of rain just before midnight , when Sarah Vaughan <WSD>was</WSD> in the midst of her first number , scattered the more timid members of the audience briefly , but at this hour and with Sarah on the stand , most of the listeners did n't care whether they got wet . 
Meaning of the word marked with <WSD> tags:  have the quality of being; (copula, used with an adjective or a predicate noun)