Problem: What are the most important words?
people strolling over shopping street with a lot of souvenir shops in the evening
Answer: evening, street, stroll

Problem: What are the most important words?
huge crop of large oranges on a tree with an orchard behind
Answer: orange, orchard, tree

Problem: What are the most important words?
A girl holds a prize won at a carnival.
Answer:
carnival, prize, win