Respuesta :
Where INTO is a preposition and night is the noun of the preposition, "into the night" is the complete prepositional phrase.
The prepositional phrase is a series of words made with a preposition and its object, which can be a noun, gerund or clause, for example in the sentence “The extra blanket is in the box under the bed” the prepositional phrase is “under the bed”, in this case in the sentence “the employees often worked late into the night” the prepositional phrase is “into the night”.
