Problem: What are the most important words?
everything in the world exists in order to end up as a book .
Answer: everything, exist, world

Problem: What are the most important words?
pack up the plaid and head to the mountains for a picnic among the leaves .
Answer: head, pack, picnic

Problem: What are the most important words?
clouds fill the sky above a city .
Answer:
city, cloud, fill, sky