What is the function of the phrase "mathematics portion" in the sentence "There are 30 questions on the mathematics portion of this exam"?

What is the function of the phrase "mathematics portion" in the sentence "There are 30 questions on the mathematics portion of this exam"?

• A. Subject
• B. Object of the preposition
• C. Noun phrase
• D. Adverbial phrase

Answer: (B)

The key idea here is how a preposition combines with its object. In this sentence, the preposition on needs something to relate to, so the following noun phrase is what the preposition governs: the mathematics portion of this exam. That entire noun phrase acts as the object of the preposition, showing what the 30 questions are about. So the function of the phrase mathematics portion (as part of that object) is to be the thing the preposition is attached to, i.e., the object of the preposition. It’s not the subject of the sentence (the sentence uses there + are to express existence), and while it is a noun phrase, its role here is specifically as the preposition’s object.

The key idea here is how a preposition combines with its object. In this sentence, the preposition on needs something to relate to, so the following noun phrase is what the preposition governs: the mathematics portion of this exam. That entire noun phrase acts as the object of the preposition, showing what the 30 questions are about. So the function of the phrase mathematics portion (as part of that object) is to be the thing the preposition is attached to, i.e., the object of the preposition. It’s not the subject of the sentence (the sentence uses there + are to express existence), and while it is a noun phrase, its role here is specifically as the preposition’s object.