Problem: What are the most important words?
the valley heading up to a city and the ancient ruins of a city
Answer: city, head, valley

Problem: What are the most important words?
A cat is lying behind a keyboard with a computer above him.
Answer: cat, computer, keyboard, lie

Problem: What are the most important words?
An airplane in takeoff is gaining height yet seems to be motionless in the sky.
Answer:
airplane, sky, takeoff