Possessive Pronoun
A possessive pronoun is a pronoun that shows ownership. In this sentence "our" shows whose class took the field trip. "Our" is also considered an adjective since it describes the class as ours. Other possessive pronouns are: my, mine, ours, her, hers, his, its, their, theirs, your, yours. Our combines "my" and "your" making this pronoun a first person pronoun. This means the speaker is also part of the sentence.