英语句子结构问题,Shelley concludes that essay by calling poets "the

英语句子结构问题,
Shelley concludes that essay by calling poets "the unacknowledged legislators of the world,"because they bring imagination to the realm of "reasoners and mechanists.
Shelley concludes that essay by calling poets "the unacknowledged legislators of the world,这句话,从句只有essay?谓语呢?不太理解结构,