Problem: What are the most important words?
waterfalls flowing in idyllic uncontaminated environment crossing green meadows and boulders in summer
Answer: cross, environment, flow, summer, waterfall

Problem: What are the most important words?
a volunteers from the program paints a mural .
Answer: mural, paint, program, volunteer

Problem: What are the most important words?
train on a city headed
Answer:
city, head, train