What are the keywords in the following sentence? old trees with large and deep roots covered with moss in a deep forest
forest, moss, root, tree

What are the keywords in the following sentence? Skilled snowboarder in bright yellow glides smoothly down a stair rail in the snow.
rail, snow, snowboarder

What are the keywords in the following sentence? jupiter is the largest planet in solar system and has moons encircling it .
moon, planet, system

What are the keywords in the following sentence? He smiles, then shifts his gaze to someone, who stares at him with a confused expression.
expression, gaze, shift