Question

Identify the italicized word according to its class in structural linguistics.
They ate lunch (under) a pine tree.
conjunction
preposition
auxiliary
interrogative
empty word

Answer 1

Under is a "preposition".

This is correct because "under" is used to show the location of the action happening, which means that it is a preposition.

Answer 2

Preposition is the correct answer.

In the sentence ¨They ate lunch under a pine tree", under is classified as a preposition of place. It's been used to especify the place where the subject "they" had lunch. The word "under" in the sentence can be easily replaced by the words "below" or "beneath" which are also prepositions of place.