Problem: What are the most important words?
A passenger train moving down the tracks at the edge of a city.
Answer: city, move, track, train

Problem: What are the most important words?
a pair of bright red hibiscus flowers in bloom
Answer: bloom, flower, pair

Problem: What are the most important words?
beekeeper inspecting the frames for brood
Answer:
beekeeper, brood, frame, inspect