Problem: What are the most important words?
A giraffe bends down to eat some grass.
Answer: bend, eat, giraffe, grass

Problem: What are the most important words?
firefighters remain on the scene thursday morning after a fire
Answer: fire, firefighter, remain

Problem: What are the most important words?
tree roots extend across a gap to the mainland for nutrients
Answer:
extend, gap, mainland, nutrient, root