Final answer:
An adjectival phrase functions as an adjective, modifying a noun or pronoun by providing additional information. It can include adjectives, prepositional phrases, and infinitive phrases.
Step-by-step explanation:
An adjectival phrase is a group of words that functions as an adjective within a sentence. These phrases modify a noun or pronoun, providing more information about it. An adjectival phrase can consist of adjectives, prepositional phrases, or infinitive phrases - all working collectively to describe the noun.
For example, in the sentence 'The children were happy with their new toys,' the phrase 'happy with their new toys' acts as an adjectival phrase, modifying 'The children' by describing their state of contentment with the toys. When we say, 'The meeting located in the large conference room is about to start,' the phrase 'located in the large conference room' is another adjectival phrase giving us more detail about the location of the meeting.