Problem: What are the most important words?
The red train is moving down the tracks in this snowy town.
Answer: move, town, train

Problem: What are the most important words?
clock tower on stone building against a blue sky
Answer: building, clock, tower

Problem: What are the most important words?
A baby lies on her side on a small rug and giggles as she's tickled.
Answer:
lie, rug, tickle