Many viewers were revolted by the graphic violence in the film.

were 是 be 动词的过去式复数形式，在这里构成被动语态。 revolted 是动词 revolt 的过去分词形式，revolt 本意是"反抗、反叛"，引申为"使厌恶、使反感"。 by 在这里表示被动动作的执行者或原因，引出导致反感的具体内容。 were revolted by 是被动语态结构，表示"被...所反感/厌恶"。