The skyscraper that was built last year has the most extraordinary architecture. the underlined subject of this sentence is an adverbial phrase. a noun phrase. a prepositional phrase. a verb phrase.

The underlined subject of the sentence the skyscraper that was built last year is a noun phrase.When determining the type of phrase, you first need to find its center, of the most prominent word. Here, the center is skyscraper, which is a noun, which means that the whole phrase is a noun phrase.