Problem: What are the most important words?
cross on the top of old church
Answer: church, cross, top

Problem: What are the most important words?
old rustic horseshoe often hung on doors and said to bring good luck when hung the right way round
Answer: door, hang, horseshoe, luck

Problem: What are the most important words?
A train engine and several cars moving along a track in a city.
Answer:
car, engine, move, track