Answer:
The adverbial phrase is " into a piece of wood"
Step-by-step explanation:
The adverbial phrase that we can see in the sentence "Have you ever hammered a nail into a piece of wood" is an adverbial of place, this is used in the sentence with the same function as any adverb of place like backwards, behind, here, there, etc... it is easy to identify as an adverb or adverbial of place answers the question "where?".