Problem: What are the most important words?
lichen on mossy trees in a damp forest .
Answer: forest, lichen, tree

Problem: What are the most important words?
Grinning cheerfully, he shifts his gaze and grins.
Answer: gaze, grin, shift

Problem: What are the most important words?
hiker overlooking the lakes at provincial park .
Answer:
lake, overlook, park