Problem: What are the most important words?
trail on a patch of snow .
Answer: patch, snow, trail

Problem: What are the most important words?
the light shines through the coloured glass and makes patterns on the polished floor .
Answer: glass, light, pattern

Problem: What are the most important words?
an aircraft moves into position to receive fuel from cargo aircraft during a mission over country .
Answer:
aircraft, fuel, mission, move, receive