Answer:
The adverbial phrase is " into a piece of wood"
Explanation:
An adverbial phrase is a group of words that work together as an adverb they are giving the same kind of information and they have the same categories such as place, time, manner, etc... this is an adverbial phrase of place as it is explaining where the nail is being hammered, the expression means the same if an adverb is used instead, for example: Have you ever hammered a nail "there".
