A prepositional phrase comprising a preposition and a noun phrase can generally function either as an adjectival phrase or as an adverbial phrase.
The book on the table is mine. (The prepositional phrase on the table is an adjectival phrase modifying the noun phrase the book.)
Put the book on the table. (The prepositional phrase on the book is an adverbial phrase modifying the verb put.)
I used to think that this dual property of the prepositional phrase is applicable to all prepositions without exception. But then, here comes this example.
Do you have any plans during the vacation?
Which sounds awkward at best.
I thought about the reason why this sounded awkward. The reason I came up with is that the prepositional phrase during the vacation cannot modify any plans. It can only modify the verb have, thereby rendering the sentence awkward.
Can "during" ever lead a prepositional phrase that acts as an adjectival phrase?