The bourgeoisie revealed that the brutal use of human labor, which was highly praised by reactionaries during the Middle Ages, was correspondingly complemented by extreme laziness. It was the【 first】 to demonstrate what kind of achievements human activities could attain. It created wonders that were completely different from the Egyptian pyramids, Roman aqueducts, and Gothic cathedrals; it accomplished expeditions that were entirely distinct from the great migrations of peoples and the Crusades
这里的【】里的first是什么词性呢？为什么？我问ai说是形容词，但我觉得是名词