Question

We should ask the class to vote for a future feild trip destination. Identify the case of the pronoun we

Answer 1

"future" is the pronoun.

A pronoun describes a noun, a noun is a person, place, or thing. 

"We should ask the class to vote for a future field trip destination"

Future describes field trip, though I guess field might be a pronoun too, but if you can only pick one, then go with future  <span />