Problem: What are the most important words?
fast motion of grey clouds which covers sky at early morning before sunrise .
Answer: cloud, cover, morning, sky, sunrise

Problem: What are the most important words?
fog creeping in from the mountains as turns into evening .
Answer: evening, fog, mountain

Problem: What are the most important words?
jockeys and animal compete during day of festival
Answer:
animal, day, festival, jockey